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Kumar S, Nivedan A, Singh A, Kumar Y, Malhotra P, Tondusson M, Freysz E, Kumar S. Optical damage limit of efficient spintronic THz emitters. iScience 2021; 24:103152. [PMID: 34646990 PMCID: PMC8496183 DOI: 10.1016/j.isci.2021.103152] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/25/2021] [Accepted: 09/16/2021] [Indexed: 11/04/2022] Open
Abstract
THz pulses are generated from femtosecond pulse-excited ferromagnetic/nonmagnetic spintronic heterostructures via inverse spin Hall effect. The highest possible THz signal strength from spintronic THz emitters is limited by the optical damage threshold of the corresponding heterostructures at the excitation wavelength. For the thickness-optimized spintronic heterostructure, the THz generation efficiency does not saturate with the excitation fluence even up till the damage threshold. Bilayer (Fe, CoFeB)/(Pt, Ta)-based ferromagnetic/nonmagnetic (FM/NM) spintronic heterostructures have been studied for an optimized performance for THz generation when pumped by sub-50 fs amplified laser pulses at 800 nm. Among them, CoFeB/Pt is the best combination for an efficient THz source. The optimized FM/NM spintronic heterostructure having α-phase Ta as the nonmagnetic layer shows the highest damage threshold as compared to those with Pt, irrespective of their generation efficiency. The damage threshold of the Fe/Ta heterostructure on a quartz substrate is ∼85 GW/cm2. THz generation efficiency of (CoFeB,Fe)/(Pt,Ta) spintronic film heterostructures Determination of optical damage threshold at NIR excitation Mean value of the optical damage threshold is ∼60 GW/cm2
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Affiliation(s)
- Sandeep Kumar
- Femtosecond Spectroscopy and Nonlinear Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Anand Nivedan
- Femtosecond Spectroscopy and Nonlinear Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Arvind Singh
- Femtosecond Spectroscopy and Nonlinear Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Yogesh Kumar
- Laser Science and Technology Center, Metcalfe House, Civil Lines, New Delhi 110054, India
| | - Purnima Malhotra
- Laser Science and Technology Center, Metcalfe House, Civil Lines, New Delhi 110054, India
| | - Marc Tondusson
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, 33405 Talence, France
| | - Eric Freysz
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, 33405 Talence, France
| | - Sunil Kumar
- Femtosecond Spectroscopy and Nonlinear Photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
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2
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Dróżdż P, Ślęzak M, Janus W, Szpytma M, Nayyef H, Kozioł-Rachwał A, Freindl K, Wilgocka-Ślęzak D, Korecki J, Ślęzak T. Driving the polar spin reorientation transition of ultrathin ferromagnets with antiferromagnetic-ferromagnetic phase transition of nearby FeRh alloy film. Sci Rep 2020; 10:14901. [PMID: 32913305 PMCID: PMC7484764 DOI: 10.1038/s41598-020-71912-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/20/2020] [Indexed: 11/09/2022] Open
Abstract
We show that in-plane to out-of-plane magnetization switching of a ferromagnetic layer can be driven by antiferromagnetic-ferromagnetic phase transition in a nearby FeRh system. For FeRh/Au/FeAu trilayers, the impact of the magnetic phase transition of FeRh onto the perpendicular magnetization of monoatomic FeAu superlattices is transferred across the Au spacer layer via interlayer magnetic coupling. The polar spin reorientation process of the FeAu spins driven by the magnetic phase transition in the FeRh reveals its major features; namely it is reversible and displays hysteresis.
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Affiliation(s)
- P Dróżdż
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland.
| | - M Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - W Janus
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - M Szpytma
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - H Nayyef
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - A Kozioł-Rachwał
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - K Freindl
- Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, ul. Niezapominajek 8, 30-239, Kraków, Poland
| | - D Wilgocka-Ślęzak
- Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, ul. Niezapominajek 8, 30-239, Kraków, Poland
| | - J Korecki
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
- Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, ul. Niezapominajek 8, 30-239, Kraków, Poland
| | - T Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
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Li Q, Yang M, Gong C, Chopdekar RV, N'Diaye AT, Turner J, Chen G, Scholl A, Shafer P, Arenholz E, Schmid AK, Wang S, Liu K, Gao N, Admasu AS, Cheong SW, Hwang C, Li J, Wang F, Zhang X, Qiu Z. Patterning-Induced Ferromagnetism of Fe 3GeTe 2 van der Waals Materials beyond Room Temperature. NANO LETTERS 2018; 18:5974-5980. [PMID: 30114354 DOI: 10.1021/acs.nanolett.8b02806] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Magnetic van der Waals (vdW) materials have emerged as promising candidates for spintronics applications, especially after the recent discovery of intrinsic ferromagnetism in monolayer vdW materials. There has been a critical need for tunable ferromagnetic vdW materials beyond room temperature. Here, we report a real-space imaging study of itinerant ferromagnet Fe3GeTe2 and the enhancement of its Curie temperature well above ambient temperature. We find that the magnetic long-range order in Fe3GeTe2 is characterized by an unconventional out-of-plane stripe-domain phase. In Fe3GeTe2 microstructures patterned by a focused ion beam, the out-of-plane stripe domain phase undergoes a surprising transition at 230 K to an in-plane vortex phase that persists beyond room temperature. The discovery of tunable ferromagnetism in Fe3GeTe2 materials opens up vast opportunities for utilizing vdW magnets in room-temperature spintronics devices.
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Affiliation(s)
- Qian Li
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Mengmeng Yang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Cheng Gong
- Nano-Scale Science and Engineering Center (NSEC) , University of California , 3112 Etcheverry Hall , Berkeley , California 94720 , United States
| | | | | | | | - Gong Chen
- Department of Physics , University of California , Davis , California 95616 , United States
| | | | | | | | | | - Sheng Wang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Kai Liu
- Department of Physics , University of California , Davis , California 95616 , United States
- Department of Physics , Georgetown University , Washington , D.C. 20057 , United States
| | - Nan Gao
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Alemayehu S Admasu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Chanyong Hwang
- Korea Research Institute of Standards and Science , Yuseong, Daejeon 305-340 , Republic of Korea
| | - Jia Li
- International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , China
| | - Feng Wang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Xiang Zhang
- Nano-Scale Science and Engineering Center (NSEC) , University of California , 3112 Etcheverry Hall , Berkeley , California 94720 , United States
| | - Ziqiang Qiu
- Department of Physics , University of California , Berkeley , California 94720 , United States
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Genoni P, Genuzio F, Menteş TO, Santos B, Sala A, Lenardi C, Locatelli A. Magnetic Patterning by Electron Beam-Assisted Carbon Lithography. ACS APPLIED MATERIALS & INTERFACES 2018; 10:27178-27187. [PMID: 30019889 DOI: 10.1021/acsami.8b07485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report on the proof of principle of a scalable method for writing the magnetic state by electron-stimulated molecular dissociative adsorption on ultrathin Co on Re(0001). Intense microfocused low-energy electron beams are used to promote the formation of surface carbides and graphitic carbon through the fragmentation of carbon monoxide. Upon annealing at the CO desorption temperature, carbon persists in the irradiated areas, whereas the clean surface is recovered elsewhere, giving origin to chemical patterns with nanometer-sharp edges. The accumulation of carbon is found to induce an in-plane to out-of-plane spin reorientation transition in Co, manifested by the appearance of striped magnetic domains. Irradiation at doses in excess of 1000 L of CO followed by ultrahigh vacuum annealing at 380 °C determines the formation of a graphitic overlayer in the irradiated areas, under which Co exhibits out-of-plane magnetic anisotropy. Domains with opposite magnetization are separated here by chiral Neél walls. Our fabrication protocol adds lateral control to spin reorientation transitions, permitting to tune the magnetic anisotropy within arbitrary regions of mesoscopic size. We envisage applications in the nano-engineering of graphene-spaced stacks exhibiting the desired magnetic state and properties.
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Affiliation(s)
- Pietro Genoni
- CIMAINA, Department of Physics , Università degli Studi di Milano , via Celoria 16 , I-20133 Milan , Italy
| | - Francesca Genuzio
- Elettra-Sincrotrone Trieste , S.S. 14 km 163.5 in AREA Science Park , Basovizza, I-34149 Trieste , Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone Trieste , S.S. 14 km 163.5 in AREA Science Park , Basovizza, I-34149 Trieste , Italy
| | - Benito Santos
- Elettra-Sincrotrone Trieste , S.S. 14 km 163.5 in AREA Science Park , Basovizza, I-34149 Trieste , Italy
| | - Alessandro Sala
- Elettra-Sincrotrone Trieste , S.S. 14 km 163.5 in AREA Science Park , Basovizza, I-34149 Trieste , Italy
- Department of Physics , Università degli Studi di Trieste , via Valerio 2 , I-34127 Trieste , Italy
| | - Cristina Lenardi
- CIMAINA, Department of Physics , Università degli Studi di Milano , via Celoria 16 , I-20133 Milan , Italy
| | - Andrea Locatelli
- Elettra-Sincrotrone Trieste , S.S. 14 km 163.5 in AREA Science Park , Basovizza, I-34149 Trieste , Italy
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5
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Optimized Spintronic Terahertz Emitters Based on Epitaxial Grown Fe/Pt Layer Structures. Sci Rep 2018; 8:1311. [PMID: 29358715 PMCID: PMC5778033 DOI: 10.1038/s41598-018-19432-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 01/02/2018] [Indexed: 11/08/2022] Open
Abstract
We report on generation of pulsed broadband terahertz radiation utilizing the inverse spin hall effect in Fe/Pt bilayers on MgO and sapphire substrates. The emitter was optimized with respect to layer thickness, growth parameters, substrates and geometrical arrangement. The experimentally determined optimum layer thicknesses were in qualitative agreement with simulations of the spin current induced in the ferromagnetic layer. Our model takes into account generation of spin polarization, spin diffusion and accumulation in Fe and Pt and electrical as well as optical properties of the bilayer samples. Using the device in a counterintuitive orientation a Si lens was attached to increase the collection efficiency of the emitter. The optimized emitter provided a bandwidth of up to 8 THz which was mainly limited by the low-temperature-grown GaAs (LT-GaAS) photoconductive antenna used as detector and the pulse length of the pump laser. The THz pulse length was as short as 220 fs for a sub 100 fs pulse length of the 800 nm pump laser. Average pump powers as low as 25 mW (at a repetition rate of 75 MHz) have been used for terahertz generation. This and the general performance make the spintronic terahertz emitter compatible with established emitters based on optical rectification in nonlinear crystals.
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6
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Balk AL, Li F, Gilbert I, Unguris J, Sinitsyn NA, Crooker SA. Broadband spectroscopy of thermodynamic magnetization fluctuations through a ferromagnetic spin-reorientation transition. PHYSICAL REVIEW. X 2018; 8:10.1103/PhysRevX.8.031078. [PMID: 30984473 PMCID: PMC6459195 DOI: 10.1103/physrevx.8.031078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We use scanning optical magnetometry to study the broadband frequency spectra of spontaneous magnetization fluctuations, or "magnetization noise", in an archetypal ferromagnetic film that can be smoothly tuned through a spin reorientation transition (SRT). The SRT is achieved by laterally varying the magnetic anisotropy across an ultrathin Pt/Co/Pt trilayer, from the perpendicular to in-plane direction, via graded Ar+ irradiation. In regions exhibiting perpendicular anisotropy, the power spectrum of the magnetization noise, S(ν), exhibits a remarkably robust ν -3/2 power law over frequencies ν from 1 kHz to 1 MHz. As the SRT region is traversed, however, S(ν) spectra develop a steadily-increasing critical frequency, ν 0, below which the noise power is spectrally flat, indicating an evolving low-frequency cutoff for magnetization fluctuations. The magnetization noise depends strongly on applied in- and out-of-plane magnetic fields, revealing local anisotropies and also a field-induced emergence of fluctuations in otherwise stable ferromagnetic films. Finally, we demonstrate that higher-order correlators can be computed from the noise. These results highlight broadband spectroscopy of thermodynamic fluctuations as a powerful tool to characterize the interplay between thermal and magnetic energy scales, and as a means of characterizing phase transitions in ferromagnets.
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Affiliation(s)
- A L Balk
- National High, Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - F Li
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - I Gilbert
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J Unguris
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - N A Sinitsyn
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - S A Crooker
- National High, Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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7
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Microscopic analysis of the composition driven spin-reorientation transition in Ni(x)Pd(1-x)/Cu(001). Ultramicroscopy 2015; 159 Pt 3:503-7. [PMID: 26092084 DOI: 10.1016/j.ultramic.2015.05.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 11/21/2022]
Abstract
The spin-reorientation transition (SRT) in epitaxial NixPd1-x/Cu(001) is studied by photoemission microscopy utilizing the X-ray magnetic circular dichroism effect at the Ni L2,3 edge. In a composition/thickness wedged geometry, a composition driven SRT could be observed between 37 ML and 60 ML, and 0 and 38% of Pd. Microspectroscopy in combination with azimuthal sample rotation confirms a magnetization preference changing from the [001] to an in-plane easy axis. At this increased thickness, the domain patterns arrange comparable to SRTs in ultrathin films. The images document domains equivalent to a canted state SRT, at which an additional effect of in-plane anisotropies could be identified.
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8
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Ma S, Tan A, Deng JX, Li J, Zhang ZD, Hwang C, Qiu ZQ. Tailoring the magnetic anisotropy of Py/Ni bilayer films using well aligned atomic steps on Cu(001). Sci Rep 2015; 5:11055. [PMID: 26067408 PMCID: PMC4464147 DOI: 10.1038/srep11055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/11/2015] [Indexed: 11/09/2022] Open
Abstract
Tailoring the spin orientation at the atomic scale has been a key task in spintronics technology. While controlling the out-of-plane to in-plane spin orientation has been achieved by a precise control of the perpendicular magnetic anisotropy at atomic layer thickness level, a design and control of the in-plane magnetic anisotropy has not yet been well developed. On well aligned atomic steps of a 6° vicinal Cu(001) surface with steps parallel to the [110] axis, we grow Py/Ni overlayer films epitaxially to permit a systematic exploration of the step-induced in-plane magnetic anisotropy as a function of both the Py and the Ni film thicknesses. We found that the atomic steps from the vicinal Cu(001) induce an in-plane uniaxial magnetic anisotropy that favors both Py and Ni magnetizations perpendicular to the steps, opposite to the behavior of Co on vicinal Cu(001). In addition, thickness-dependent study shows that the Ni films exhibit different magnetic anisotropy below and above ~6 ML Ni thickness.
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Affiliation(s)
- S Ma
- 1] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2] Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - A Tan
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - J X Deng
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - J Li
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - Z D Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - C Hwang
- Korea Research Institute of Standards and Science, Yuseong, Daejeon 305-340, Korea
| | - Z Q Qiu
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
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9
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Real-time observation of domain fluctuations in a two-dimensional magnetic model system. Nat Commun 2015; 6:6832. [PMID: 25902073 PMCID: PMC4423231 DOI: 10.1038/ncomms7832] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 03/04/2015] [Indexed: 11/08/2022] Open
Abstract
Domain patterns of perpendicularly magnetized ultra-thin ferromagnetic films are often determined by the competition of the short range but strong exchange interaction favouring ferromagnetic alignment of magnetic moments and the long range but weak antiferromagnetic dipolar interaction. Detailed phase diagrams of the resulting stripe domain patterns have been evaluated in recent years; however, the domain fluctuations in these pattern forming systems have not been studied in great detail so far. Here we show that domain fluctuations can be observed in ultra-thin two-dimensional ferromagnetic Fe/Ni/Cu(001) films with perpendicular magnetization in the stripe domain phase. Non-stroboscopic time-resolved threshold photoemission electron microscopy with high temporal resolution allows analysing the dynamic fingerprint of the topological excitations in the nematic domain phase. Furthermore, proliferation of domain ending defects in the vicinity of the spin reorientation transition is witnessed.
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10
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Hoang DT, Kasperski M, Puszkarski H, Diep HT. Re-orientation transition in molecular thin films: Potts model with dipolar interaction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:056006. [PMID: 23287003 DOI: 10.1088/0953-8984/25/5/056006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We study the low-temperature behavior and the phase transition of a thin film by Monte Carlo simulation. The thin film has a simple cubic lattice structure where each site is occupied by a Potts parameter which indicates the molecular orientation of the site. We take only three molecular orientations in this paper, which correspond to the three-state Potts model. The Hamiltonian of the system includes (i) the exchange interaction J(ij) between nearest-neighbor sites i and j, (ii) the long-range dipolar interaction of amplitude D truncated at a cutoff distance r(c), and (iii) a single-ion perpendicular anisotropy of amplitude A. We allow J(ij) = J(s) between surface spins, and J(ij) = J otherwise. We show that the ground state depends on the ratio D/A and r(c). For a single layer, for a given A, there is a critical value D(c) below (above) which the ground-state (GS) configuration of molecular axes is perpendicular (parallel) to the film surface. When the temperature T is increased, a re-orientation transition occurs near D(c): the low-T in-plane ordering undergoes a transition to the perpendicular ordering at a finite T, below the transition to the paramagnetic phase. The same phenomenon is observed in the case of a film with a thickness. Comparison with the Fe/Gd experiment is given. We show that the surface phase transition can occur below or above the bulk transition depending on the ratio J(s)/J. Surface and bulk order parameters as well as other physical quantities are shown and discussed.
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Affiliation(s)
- Danh-Tai Hoang
- Laboratoire de Physique Théorique et Modélisation, Université de Cergy-Pontoise, CNRS, UMR 8089 2, Avenue Adolphe Chauvin, F-95302 Cergy-Pontoise Cedex, France.
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11
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Rybicki M, Zasada I. Noncollinear spin reorientation transition in S = 1 ferromagnetic thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:386005. [PMID: 22927564 DOI: 10.1088/0953-8984/24/38/386005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
An in-plane spin reorientation transition in thin ferromagnetic films is discussed in terms of the thermodynamics of inhomogeneous low-dimensional systems based on a Néel sublattices concept while using a spin 1 Heisenberg Hamiltonian. The model allows us to investigate in a straightforward manner the layer-dependent phenomena. In this context, we propose a model of noncollinear magnetization structure based on the appropriate distribution of the anisotropy parameters inside the Fe films on W(110). The spin reorientation transition originates at the Fe/W(110) interface and proceeds via noncollinear magnetization structure toward the surface with increasing film thickness in accordance with the experimental findings. The temperature-driven spin reorientation transition in freestanding Fe films and in Fe/W(110) systems is also discussed in detail.
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Affiliation(s)
- Marcin Rybicki
- Department of Solid State Physics, University of Lodz, Lodz, Poland
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12
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Pappas D, Glesener J, Harris V, Krebs J, Idzerda Y, Morrish A, Prinz G. Epitaxial Growth of fee Fe and Cu Films on Diamond. ACTA ACUST UNITED AC 2012. [DOI: 10.1557/proc-313-369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe growth of iron and copper films and multilayers on the (100) face of diamond has been achieved and studied by reflection high energy electron diffraction (RHEED), extended x-ray absorption fine structure (EXAFS), ferromagnetic resonance (FMR), and SQUID Magnetometry. RHEED and AES studies show that 2–3 atomic layers (AL) of Fe on C (100) forms a continuous film. The films as deposited at room temperature are disordered, and after a 350° C anneal displays a face-centered cubic structure. Subsequent layers of Cu on this epitaxial Fe film grow as an oriented, single crystal fee film. FMR and SQUID signals have been observed from the Fe films, showing that they are ferromagnetic.
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13
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Bochi G, Ballentine CA, Inglefield HE, Bogomolov SS, Thompson CV, Ohandley RC. Magnetic Anisotropy in Epitaxial Ni/Cu (100) Thin Films. ACTA ACUST UNITED AC 2012. [DOI: 10.1557/proc-313-309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTEpitaxial Ni/Cu (001) films grown on Si (001) by Molecular Beam Epitaxy were studied in-situ using the Surface Magneto-optic Kerr Effect (SMOKE) and ex-situ with a Vibrating Sample Magnetometer (VSM). Perpendicular Magnetization is observed for Ni thicknesses 15 Å ≤ h ≤ 60 Å and fully in-plane magnetization for h ≥ 70 Å when the films are characterized in-situ. The reversal in magnetic anisotropy observed in-situ at 60 Å shifts to 125 Å when the films are exposed to air. 100 Å Ni films deposited on Cu1−x-Nix alloy substrates also show a reversal in magnetic anisotropy as x is changed. These results suggest that changes in magnetic anisotropy correlate with misfit strain accommodation.
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14
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Frömter R, Hankemeier S, Oepen HP, Kirschner J. Optimizing a low-energy electron diffraction spin-polarization analyzer for imaging of magnetic surface structures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:033704. [PMID: 21456748 DOI: 10.1063/1.3534832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A newly designed scanning electron microscope with polarization analysis (SEMPA or spin-SEM) for the acquisition of magnetic images is presented. Core component is the spin detector, based on the scattering of low-energy electrons at a W(100) surface in ultrahigh vacuum. The instrument has been optimized with respect to ease of handling and efficiency. The operation and performance of a general low-energy electron diffraction (LEED) detector for SEMPA have been modeled in order to find the optimum operating parameters and to predict the obtainable image asymmetry. Based on the energy dependence of the secondary electron polarization and intensity, the detector output is simulated. For our instrument with optimized performance we demonstrate experimentally 8.6% polarization asymmetry in the domain structure of an iron whisker. This corresponds to 17.2% image contrast, in excellent agreement with the predicted simulated value. A contrast to noise ratio of 27 is achieved at 5 ms acquisition time per pixel.
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Affiliation(s)
- Robert Frömter
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany.
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15
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Donzelli O, Vatucello G, Nizzoli F, Palmeri D, Lucari F, D'Orazio F. Magnetic Stripe Domains in Fe/Ni Multilayers. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-475-513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTMagnetic Fe/Ni multilayers, investigated by Magnetic Force Microscopy (MFM), show a stripe domains structure in which the magnetization is oriented in the film plane. This structure is attributed to the equilibrium configuration between competing in-plane anisotropy of the Ni layers and perpendicular anisotropy due to the thin Fe layers.
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Slezak T, Slezak M, Zajac M, Freindl K, Kozioł-Rachwał A, Matlak K, Spiridis N, Wilgocka-Slezak D, Partyka-Jankowska E, Rennhofer M, Chumakov AI, Stankov S, Rüffer R, Korecki J. Noncollinear magnetization structure at the thickness-driven spin-reorientation transition in epitaxial Fe films on W(110). PHYSICAL REVIEW LETTERS 2010; 105:027206. [PMID: 20867738 DOI: 10.1103/physrevlett.105.027206] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Indexed: 05/29/2023]
Abstract
An in-plane spin-reorientation transition occurring during the growth of epitaxial Fe films on W(110) was studied in situ by using the nuclear resonant scattering of synchrotron radiation. The spin-reorientation transition originates at the Fe/W(110) interface and proceeds via a noncollinear spin structure resembling a planar domain wall that propagates towards the surface with increasing film thickness.
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Affiliation(s)
- T Slezak
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
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17
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Winkelmann A, Hartung D, Engelhard H, Chiang CT, Kirschner J. High efficiency electron spin polarization analyzer based on exchange scattering at FeW(001). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:083303. [PMID: 19044342 DOI: 10.1063/1.2949877] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on a compact electron spin analyzer based on exchange scattering from a magnetic surface. The heart of the detector is an Fe(001) thin film grown on W(001) with chemisorbed oxygen in the p(1 x 1) structure. The device is mounted at the exit of an energy dispersive analyzer and works at a scattering energy of about 13.5 eV. Its figure of merit is 2 x 10(-3), combined with an excellent stability of more than 2 weeks in UHV.
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Affiliation(s)
- A Winkelmann
- Max-Planck-Institut fur Mikrostrukturphysik, Weinberg 2, D-06120 Halle(Saale), Germany
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18
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Choi J, Wu J, Won C, Wu YZ, Scholl A, Doran A, Owens T, Qiu ZQ. Magnetic bubble domain phase at the spin reorientation transition of ultrathin Fe/Ni/Cu(001) film. PHYSICAL REVIEW LETTERS 2007; 98:207205. [PMID: 17677736 DOI: 10.1103/physrevlett.98.207205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 03/01/2007] [Indexed: 05/16/2023]
Abstract
Magnetic domain phases of ultrathin Fe/Ni/Cu(001) are studied using photoemission electron microscopy at the spin reorientation transition (SRT). We observe a new magnetic phase of bubble domains within a narrow SRT region after applying a nearly in-plane magnetic field pulse to the sample. By applying the magnetic field pulse along different directions, we find that the bubble domain phase exists only if the magnetic field direction is less than approximately 10 degrees relative to the sample surface. A temperature dependent measurement shows that the bubble domain phase becomes unstable above 370 K.
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Affiliation(s)
- J Choi
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
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19
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Iunin YL, Kabanov YP, Nikitenko VI, Cheng XM, Clarke D, Tretiakov OA, Tchernyshyov O, Shapiro AJ, Shull RD, Chien CL. Asymmetric domain nucleation and unusual magnetization reversal in ultrathin Co films with perpendicular anisotropy. PHYSICAL REVIEW LETTERS 2007; 98:117204. [PMID: 17501087 DOI: 10.1103/physrevlett.98.117204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Indexed: 05/15/2023]
Abstract
We report unexpected phenomena during magnetization reversal in ultrathin Co films and Co/Pt multilayers with perpendicular anisotropy. Using magneto-optical Kerr microscopy and magnetic force microscopy we have observed asymmetrical nucleation centers where the reversal begins for one direction of the field only and is characterized by an acute asymmetry of domain-wall mobility. We have also observed magnetic domains with a continuously varying average magnetization, which can be explained in terms of the coexistence of three magnetic phases: up, down, and striped.
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Affiliation(s)
- Y L Iunin
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka 142432, Russia
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20
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Portmann O, Vaterlaus A, Pescia D. Observation of stripe mobility in a dipolar frustrated ferromagnet. PHYSICAL REVIEW LETTERS 2006; 96:047212. [PMID: 16486892 DOI: 10.1103/physrevlett.96.047212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Indexed: 05/06/2023]
Abstract
We have discovered two novel aspects of the stripe-domain to paramagnetic transition in perpendicularly magnetized Fe films on Cu(100). First, the width of the stripes carrying oppositely oriented spins decreases, close to the transition temperature, with a power law. Second, in a small temperature interval close to the transition temperature, the stripes--which form stationary patterns at low temperatures--become mobile. Various theoretical works have predicted stripe mobility in similar frustrated systems but no direct proof of this phenomenon has been reported so far.
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Affiliation(s)
- O Portmann
- Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland
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21
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Leaf G, Kaper H, Yan M, Novosad V, Vavassori P, Camley RE, Grimsditch M. Dynamic origin of stripe domains. PHYSICAL REVIEW LETTERS 2006; 96:017201. [PMID: 16486507 DOI: 10.1103/physrevlett.96.017201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Indexed: 05/06/2023]
Abstract
We investigate stripe domain formation in nanometer sized Co bars. The magnetic equilibrium states and the magnetic spin wave frequencies are obtained from micromagnetic-like simulations. We find that the lowest frequency standing-wave mode has the same spatial structure as the stripe domains at remanence and it goes soft at the field where the stripe domains emerge. We show, therefore, that the final domain structure at remanence, which is not the configuration with lowest energy, is predicted from a high-field analysis of the frequencies of the standing spin waves.
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Affiliation(s)
- G Leaf
- Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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22
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Cr adsorption effect of magnetic property of Fe/Cu(001). E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2006. [DOI: 10.1380/ejssnt.2006.345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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24
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25
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Wu YZ, Won C, Scholl A, Doran A, Zhao HW, Jin XF, Qiu ZQ. Magnetic stripe domains in coupled magnetic sandwiches. PHYSICAL REVIEW LETTERS 2004; 93:117205. [PMID: 15447377 DOI: 10.1103/physrevlett.93.117205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Indexed: 05/24/2023]
Abstract
Magnetic stripe domains in the spin reorientation transition region are investigated in (Fe/Ni)/Cu(001) and Co/Cu/(Fe/Ni)/Cu(001) using photoemission electron microscopy. For (Fe/Ni)/Cu(001), the stripe domain width decreases exponentially as the Fe/Ni film approaches the spin reorientation transition point. For Co/Cu/(Fe/Ni)/Cu(001), the Fe/Ni stripe orientation is aligned with the Co in-plane magnetization, and the stripe domain width decreases exponentially with increasing the interlayer coupling between the Fe/Ni and Co films. By considering magnetic stripes within an in-plane magnetic field, we reveal a universal dependence of the stripe domain width on the magnetic anisotropy and on the interlayer coupling.
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Affiliation(s)
- Y Z Wu
- Department of Physics, University of California Berkeley, Berkeley California 94720, USA
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26
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Tikhonov AM, Pingali SV, Schlossman ML. Molecular ordering and phase transitions in alkanol monolayers at the water–hexane interface. J Chem Phys 2004; 120:11822-38. [PMID: 15268217 DOI: 10.1063/1.1752888] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interface between bulk water and bulk hexane solutions of n-alkanols (H(CH(2))(m)OH, where m=20, 22, 24, or 30) is studied with x-ray reflectivity, x-ray off-specular diffuse scattering, and interfacial tension measurements. The alkanols adsorb to the interface to form a monolayer. The highest density, lowest temperature monolayers contain alkanol molecules with progressive disordering of the chain from the -CH(2)OH to the -CH(3) group. In the terminal half of the chain that includes the -CH(3) group the chain density is similar to that observed in bulk liquid alkanes just above their freezing temperature. The density in the alkanol headgroup region is 10% greater than either bulk water or the ordered headgroup region found in alkanol monolayers at the water-vapor interface. We conjecture that this higher density is a result of water penetration into the headgroup region of the disordered monolayer. A ratio of 1:3 water to alkanol molecules is consistent with our data. We also place an upper limit of one hexane to five or six alkanol molecules mixed into the alkyl chain region of the monolayer. In contrast, H(CH(2))(30)OH at the water-vapor interface forms a close-packed, ordered phase of nearly rigid rods. Interfacial tension measurements as a function of temperature reveal a phase transition at the water-hexane interface with a significant change in interfacial excess entropy. This transition is between a low temperature interface that is nearly fully covered with alkanols to a higher temperature interface with a much lower density of alkanols. The transition for the shorter alkanols appears to be first order whereas the transition for the longer alkanols appears to be weakly first order or second order. The x-ray data are consistent with the presence of monolayer domains at the interface and determine the domain coverage (fraction of interface covered by alkanol domains) as a function of temperature. This temperature dependence is consistent with a theoretical model for a second order phase transition that accounts for the domain stabilization as a balance between line tension and long range dipole forces. Several aspects of our measurements indicate that the presence of domains represents the appearance of a spatially inhomogeneous phase rather than the coexistence of two homogeneous phases.
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27
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Loh KK, Kawasaki K, Bishop AR, Lookman T, Saxena A, Nussinov Z, Schmalian J. Glassy behavior in systems with Kac-type step-function interaction. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:010501. [PMID: 14995597 DOI: 10.1103/physreve.69.010501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2002] [Revised: 05/20/2003] [Indexed: 05/24/2023]
Abstract
We study a system with a weak, long-ranged repulsive Kac-type step-function interaction within the framework of a replicated effective phi(4) theory. The occurrence of extensive configurational entropy or an exponentially large number of metastable minima in the free energy (characteristic of a glassy state), is demonstrated. The underlying mechanism of mesoscopic patterning and defect organizations is discussed.
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Affiliation(s)
- Kok-Kiong Loh
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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28
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Dorantes-Dávila J, Dreyssé H, Pastor GM. Magnetic anisotropy of transition-metal interfaces from a local perspective: reorientation transitions and spin-canted phases in Pd capped Co films on Pd(111). PHYSICAL REVIEW LETTERS 2003; 91:197206. [PMID: 14611612 DOI: 10.1103/physrevlett.91.197206] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2002] [Indexed: 05/24/2023]
Abstract
Layer-resolved self-consistent electronic calculations of magnetic anisotropy energy (MAE) provide new insight to the off-plane magnetization observed in Pd capped Co films on Pd(111). We demonstrate that the transition from perpendicular to in-plane phases with increasing film thickness involves an intermediate spin-canted phase. The interfaces responsible for the stability of the off-plane easy axes are characterized microscopically. A local analysis of the MAEs reveals an unexpected internal magnetic structure of the Co-Pd interfaces in which the magnetic moments and spin-orbit interactions at the Pd atoms play a crucial role.
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Affiliation(s)
- J Dorantes-Dávila
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, San Luis Potosí, Mexico
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29
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Enders A, Peterka D, Repetto D, Lin N, Dmitriev A, Kern K. Temperature dependence of the surface anisotropy of Fe ultrathin films on Cu(001). PHYSICAL REVIEW LETTERS 2003; 90:217203. [PMID: 12786584 DOI: 10.1103/physrevlett.90.217203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Indexed: 05/24/2023]
Abstract
We report an experimental approach to separate temperature dependent reversible and irreversible contributions to the perpendicular magnetic anisotropy of Fe films grown at low temperatures on Cu(001) substrates. The surface anisotropy K(S)(T) is found to decrease linearly with temperature, causing a thermally induced spin reorientation into the plane. The irreversible shift of the spin reorientation transition and the coercivity of the iron films are directly correlated to the increasing Fe island size during annealing. The increased coercivity is discussed in terms of domain wall energy inhomogeneities provided by the islands.
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Affiliation(s)
- A Enders
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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30
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Kisielewski M, Maziewski A, Tekielak M, Wawro A, Baczewski LT. New possibilities for tuning ultrathin cobalt film magnetic properties by a noble metal overlayer. PHYSICAL REVIEW LETTERS 2002; 89:087203. [PMID: 12190497 DOI: 10.1103/physrevlett.89.087203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2002] [Indexed: 05/23/2023]
Abstract
Complementary multiscale magneto-optical studies based on the polar Kerr effect are carried out on an ultrathin cobalt wedge covered with a silver wedge and subsequently with the Au thick layer. A few monolayers of Ag are found to have a substantial effect on magnetic anisotropy, the coercivity field, and Kerr rotation. The silver overlayer thickness-driven magnetic reorientation from easy axis to easy plane generates a new type of 90 degrees magnetic wall for cobalt thicknesses between 1.3 and 1.8 nm. The tuning of the wall width in a wide range is possible. Tailoring of the overlayer structure can be used for ultrathin film magnetic patterning.
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Affiliation(s)
- M Kisielewski
- Institute of Experimental Physics, University of Bialystok, Lipowa 41, 15-424 Bialystok, Poland
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31
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32
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Bogdanov A, R�ssler U, M�ller KH. Induced Anisotropy, Reorientation Transitions, and Domains in Magnetic Films and Multilayers. ACTA ACUST UNITED AC 2002. [DOI: 10.1002/1521-396x(200202)189:2<397::aid-pssa397>3.0.co;2-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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Scanning electron microscope with polarization analysis: Micromagnetic structures in ultrathin films. ACTA ACUST UNITED AC 2002. [DOI: 10.1116/1.1519863] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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34
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García N, Osipov VV, Ponizovskaya EV, del Moral A. Chaotic domain patterns in periodic inhomogeneous magnetic films. PHYSICAL REVIEW LETTERS 2001; 86:4926-4929. [PMID: 11384383 DOI: 10.1103/physrevlett.86.4926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2000] [Indexed: 05/23/2023]
Abstract
A study of domain structures in thin inhomogeneous ferromagnetic films is presented. It is shown that smooth and small inhomogeneities in the exchange and anisotropy parameters yield very complex domain structures. We show that the domain walls are fixed near certain inhomogeneities but do not repeat their space distribution. We found that there are metastable chaotic domain patterns in periodic inhomogeneous films. These results are relevant for magnetoresistive devices.
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Affiliation(s)
- N García
- Laboratorio de Física de Sistemas Pequeños y Nanotecnología, C.S.I.C., c/Serrano 144, 28006 Madrid, Spain
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35
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Schmalian J, Wolynes PG. Stripe glasses: self-generated randomness in a uniformly frustrated system. PHYSICAL REVIEW LETTERS 2000; 85:836-839. [PMID: 10991411 DOI: 10.1103/physrevlett.85.836] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2000] [Indexed: 05/23/2023]
Abstract
We show that a system with competing interactions on different length scales, relevant to the formation of stripes in doped Mott insulators, undergoes a self-generated glass transition which is caused by the frustrated nature of the interactions and not related to the presence of quenched disorder. An exponentially large number of metastable configurations is found, leading to a slow, landscape dominated long time relaxation and a breakup of the system into a disordered inhomogeneous state.
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Affiliation(s)
- J Schmalian
- Department of Physics and Astronomy and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
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36
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Matsuyama H, Haginoya C, Koike K. Microscopic imaging of Fe magnetic domains exchange coupled with those in a NiO(001) surface. PHYSICAL REVIEW LETTERS 2000; 85:646-649. [PMID: 10991361 DOI: 10.1103/physrevlett.85.646] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/1999] [Indexed: 05/23/2023]
Abstract
We revealed the micromagnetic structure of an Fe thin film exchange interacting with the spins of a fully compensated (001) surface of antiferromagnetic NiO. The interface exchange interaction causes the Fe domains to follow the NiO domains. The Fe spin polarization is in plane and the spin polarization in each domain is roughly perpendicular to an easy-spin axis of the NiO. These results agree with numerically calculated spin directions. Our numerical results also show that the NiO spins at the interface cant from the easy-spin axis towards the Fe spin because of exchange coupling.
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Affiliation(s)
- H Matsuyama
- Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan
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37
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Vedmedenko EY, Oepen HP, Ghazali A, Lévy JC, Kirschner J. Magnetic microstructure of the spin reorientation transition: a computer experiment. PHYSICAL REVIEW LETTERS 2000; 84:5884-5887. [PMID: 10991079 DOI: 10.1103/physrevlett.84.5884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/1999] [Indexed: 05/23/2023]
Abstract
The scenario of the spin reorientation in two-dimensional films within first-order anisotropy approximation is theoretically studied by means of Monte Carlo simulations. The magnetic microstructure is investigated as a function of the ratio of the perpendicular anisotropy energy to the dipolar one. If the anisotropy dominates, out-of-plane domains will be found while in-plane vortices appear for a vanishing anisotropy. In the range of comparable anisotropy and dipolar energies a complex domain pattern evolves yielding a continuous transition between the two structures. The structure with equally distributed magnetic moment orientations is stable at the point where anisotropy and dipolar energies cancel each other.
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Affiliation(s)
- E Y Vedmedenko
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany.
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38
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Vaterlaus A, Stamm C, Maier U, Pini MG, Politi P, Pescia D. Two-step disordering of perpendicularly magnetized ultrathin films. PHYSICAL REVIEW LETTERS 2000; 84:2247-2250. [PMID: 11017255 DOI: 10.1103/physrevlett.84.2247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/1999] [Indexed: 05/23/2023]
Abstract
We have imaged the stripe domain structure of perpendicularly magnetized fcc ultrathin Fe films grown on Cu(100). The stripe phase has a strong local orientational order and sustains the two kinds of fluctuations predicted by Abanov et al. [Phys. Rev. B 51, 1023 (1995)]: meandering and dislocations. Before reaching the Curie temperature, the stripes transform into a new and so far unobserved domain structure, characterized by domains with predominantly square corners. We argue that this phase is the tetragonal liquid phase proposed by Abanov et al. to separate the stripe phase from the paramagnetic phase. This two-step disordering is reminiscent of a two-dimensional melting process.
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Affiliation(s)
- A Vaterlaus
- Laboratorium für Festkörperphysik, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
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39
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Blinov L, Fridkin VM, Palto SP, Bune A, Dowben P, Ducharme S. Two-dimensional ferroelectrics. ACTA ACUST UNITED AC 2000. [DOI: 10.3367/ufnr.0170.200003b.0247] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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40
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41
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Chapter 15 Ultrathin magnetic structures—magnetism and electronic properties. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1571-0785(97)80018-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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42
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Lorenz R, Hafner J. Magnetic structure and anisotropy of thin Fe films on Cu(001) substrates. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:15937-15949. [PMID: 9985663 DOI: 10.1103/physrevb.54.15937] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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43
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Dunn JH, Arvanitis D, Mårtensson N. Magnetism of thin Fe films on Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R11157-R11160. [PMID: 9985010 DOI: 10.1103/physrevb.54.r11157] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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44
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Újfalussy B, Szunyogh L, Weinberger P. Magnetic anisotropy in Fe/Cu(001) overlayers and interlayers: The high-moment ferromagnetic phase. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:9883-9890. [PMID: 9984723 DOI: 10.1103/physrevb.54.9883] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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Luce TA, Hübner W, Bennemann KH. Theory for Spin-Polarized Oscillations in Nonlinear Optics due to Quantum Well States. PHYSICAL REVIEW LETTERS 1996; 77:2810-2813. [PMID: 10062051 DOI: 10.1103/physrevlett.77.2810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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46
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Bode M, Pascal R, Dreyer M, Wiesendanger R. Nanostructural and local electronic properties of Fe/W(110) correlated by scanning tunneling spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R8385-R8388. [PMID: 9984601 DOI: 10.1103/physrevb.54.r8385] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Millev Y, Kirschner J. Reorientation transitions in ultrathin ferromagnetic films by thickness- and temperature-driven anisotropy flows. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:4137-4145. [PMID: 9986316 DOI: 10.1103/physrevb.54.4137] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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48
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Arlett J, Whitehead JP, MacIsaac AB, De'Bell K. Phase diagram for the striped phase in the two-dimensional dipolar Ising model. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:3394-3402. [PMID: 9986239 DOI: 10.1103/physrevb.54.3394] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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49
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MacIsaac AB, Whitehead JP, De'Bell K, Poole PH. Phase Diagram for a Magnetic Thin Film with Dipolar Interactions and Magnetic Surface Anisotropy. PHYSICAL REVIEW LETTERS 1996; 77:739-742. [PMID: 10062890 DOI: 10.1103/physrevlett.77.739] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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50
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Kirilyuk A, Giergiel J, Shen J, Straub M, Kirschner J. Growth of stabilized gamma -Fe films and their magnetic properties. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:1050-1063. [PMID: 9985373 DOI: 10.1103/physrevb.54.1050] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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