1
|
Szpytma M, Ślęzak M, Janus W, Nayyef H, Ślęzak T, Mandziak A, Zając M, Wilgocka-Ślęzak D, Menteş TO, Jugovac M, Locatelli A, Kozioł-Rachwał A. Transfer of magnetic anisotropy in epitaxial Co/NiO/Fe trilayers. Sci Rep 2024; 14:1680. [PMID: 38243038 PMCID: PMC10798992 DOI: 10.1038/s41598-024-51896-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 01/10/2024] [Indexed: 01/21/2024] Open
Abstract
The magnetic properties of Co(10 Å)/NiO(40 Å)/Fe trilayer epitaxially grown on W(110) substrate were investigated with use of x-ray magnetic linear dichroism (XMLD) and x-ray magnetic circular dichroism (XMCD). We showed that magnetic anisotropy of Fe film that can be controlled by a thickness-driven spin reorientation transition is transferred via interfacial exchange coupling not only to NiO layer but further to ferromagnetic Co overlayer as well. Similarly, a temperature driven spin reorientation of Fe sublayer induces a reorientation of NiO spin orientation and simultaneous switching of the Co magnetization direction. Finally, by element specific XMCD and XMLD magnetic hysteresis loop measurements we proved that external magnetic field driven reorientation of Fe and Co magnetizations as well as NiO Néel vector are strictly correlated and magnetic anisotropy fields of Fe and Co sublayers are identical despite the different crystal structures.
Collapse
Affiliation(s)
- M Szpytma
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland.
| | - M Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - W Janus
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - H Nayyef
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - T Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - A Mandziak
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Krakow, Poland
| | - M Zając
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Krakow, Poland
| | - D Wilgocka-Ślęzak
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - T O Menteş
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - M Jugovac
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - A Locatelli
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - A Kozioł-Rachwał
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| |
Collapse
|
2
|
Quintana M, Berger A. Experimental Observation of Critical Scaling in Magnetic Dynamic Phase Transitions. PHYSICAL REVIEW LETTERS 2023; 131:116701. [PMID: 37774283 DOI: 10.1103/physrevlett.131.116701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/16/2023] [Accepted: 08/01/2023] [Indexed: 10/01/2023]
Abstract
We explore the critical behavior of dynamic phase transitions in ultrathin uniaxial Co films. Our data demonstrate the occurrence of critical fluctuations, which define the critical regime, and in which we conduct a scaling analysis of the dynamic order parameter Q, utilizing a dynamic analog to the Arrott-Noakes equation of state. Our results show dynamic critical exponents that agree with the 2D Ising model as theoretically predicted. However, equilibrium critical exponents of our sample agree with the 3D Ising model. We argue that these differences between dynamic and thermodynamic behavior are due to fundamentally different length scales at which dimensional crossovers occur.
Collapse
Affiliation(s)
- M Quintana
- CIC nanoGUNE BRTA, E-20018 Donostia-San Sebastián, Spain
| | - A Berger
- CIC nanoGUNE BRTA, E-20018 Donostia-San Sebastián, Spain
| |
Collapse
|
3
|
Nayyef H, Świerkosz E, Janus W, Klimeczek A, Szpytma M, Zając M, Dróżdż P, Kozioł-Rachwał A, Ślęzak T, Ślęzak M. Tunable interplay between exchange coupling and uniaxial magnetic anisotropy in epitaxial CoO/Au/Fe trilayers. Sci Rep 2023; 13:10902. [PMID: 37407653 PMCID: PMC10322835 DOI: 10.1038/s41598-023-38098-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023] Open
Abstract
We show that the interaction between ferromagnetic Fe(110) and antiferromagnetic CoO(111) sublayers can be mediated and precisely tuned by a nonmagnetic Au spacer. Our results prove that the thickness of the Fe and Au layers can be chosen to modify the effective anisotropy of the Fe layer and the strength of the exchange bias interaction between Fe and CoO sublayers. Well-defined and tailorable magnetic anisotropy of the ferromagnet above Néel temperature of the antiferromagnet is a determining factor that governs exchange bias and interfacial CoO spins orientation at low temperatures. In particular, depending on the room temperature magnetic state of Fe, the low-temperature exchange bias in a zero-field cooled system can be turned "off" or "on". The other way around, we show that exchange bias can be the dominating magnetic anisotropy source for the ferromagnet and it is feasible to induce a 90-degree rotation of the easy axis as compared to the initial, exchange bias-free easy axis orientation.
Collapse
Affiliation(s)
- H Nayyef
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - E Świerkosz
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - W Janus
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - A Klimeczek
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - M Szpytma
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - M Zając
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Kraków, Poland
| | - P Dróżdż
- Institute of Physics, Maria Curie-Sklodowska University, Lublin, Poland
| | - A Kozioł-Rachwał
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - T Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
| | - M Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland.
| |
Collapse
|
4
|
Ślęzak M, Dróżdż P, Matlak K, Kozioł-Rachwał A, Sasikala Devi AA, Alatalo M, Ślęzak T. From Termination Dependent Chemical Sensitivity of Spin Orientation in All-bcc Fe/Co Magnetic Superlattices toward the Concept of an Artificial Surface of a Ferromagnet. J Phys Chem Lett 2022; 13:8522-8528. [PMID: 36067031 PMCID: PMC9486937 DOI: 10.1021/acs.jpclett.2c02139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/01/2022] [Indexed: 06/11/2023]
Abstract
Adsorption of gases on the surface of all-bcc (Fe/Co)N superlattices drives the in-plane, 90° magnetization rotation of the bulk-like Fe(110) supporting ferromagnet. Both experimental and theoretical results prove that terminating the surface of (Fe/Co)N superlattices either by Co or by Fe switches "ON" or "OFF" the spin orientation sensitivity to adsorption. Results indicate that purely surface limited adsorption processes strongly modify the magnetic anisotropy of the entire (Fe/Co)N superlattice, which acts as a kind of "artificial" surface of the bulky Fe(110) ferromagnet. Such an artificial magnetic surface anisotropy concept not only enhances the surface contribution in classical surface-bulk competition but also provides its additional chemical sensitivity.
Collapse
Affiliation(s)
- M. Ślęzak
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
| | - P. Dróżdż
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
| | - K. Matlak
- National
Synchrotron Radiation Centre SOLARIS, Jagiellonian
University, 30-392 Kraków, Poland
| | - A. Kozioł-Rachwał
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
| | - A. A. Sasikala Devi
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90014 Oulu, Finland
| | - M. Alatalo
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90014 Oulu, Finland
| | - T. Ślęzak
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
| |
Collapse
|
5
|
Slęzak M, Dróżdż P, Janus W, Nayyef H, Kozioł-Rachwał A, Szpytma M, Zając M, Menteş TO, Genuzio F, Locatelli A, Slęzak T. Fine tuning of ferromagnet/antiferromagnet interface magnetic anisotropy for field-free switching of antiferromagnetic spins. NANOSCALE 2020; 12:18091-18095. [PMID: 32856646 DOI: 10.1039/d0nr04193a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We show that in a uniform thickness NiO(111)/Fe(110) epitaxial bilayer system, at given temperature near 300 K, two magnetic states with orthogonal spin orientations can be stabilized in antiferromagnetic NiO. Field-free, reversible switching between these two antiferromagnetic states is demonstrated. The observed phenomena arise from the unique combination of precisely tuned interface magnetic anisotropy, thermal hysteresis of spin reorientation transition and interfacial ferromagnet/antiferromagnet exchange coupling. The possibility of field-free switching between two magnetic states in an antiferromagnet is fundamentally interesting and can lead to new ideas in heat assisted magnetic recording technology.
Collapse
Affiliation(s)
- M Slęzak
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - P Dróżdż
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - W Janus
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - H Nayyef
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - A Kozioł-Rachwał
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - M Szpytma
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| | - M Zając
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Kraków, Poland
| | - T O Menteş
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - F Genuzio
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - A Locatelli
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - T Slęzak
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Peng B, Zhou Z, Nan T, Dong G, Feng M, Yang Q, Wang X, Zhao S, Xian D, Jiang ZD, Ren W, Ye ZG, Sun NX, Liu M. Deterministic Switching of Perpendicular Magnetic Anisotropy by Voltage Control of Spin Reorientation Transition in (Co/Pt) 3/Pb(Mg 1/3Nb 2/3)O 3-PbTiO 3 Multiferroic Heterostructures. ACS NANO 2017; 11:4337-4345. [PMID: 28394574 DOI: 10.1021/acsnano.7b01547] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One of the central challenges in realizing multiferroics-based magnetoelectric memories is to switch perpendicular magnetic anisotropy (PMA) with a control voltage. In this study, we demonstrate electrical flipping of magnetization between the out-of-plane and the in-plane directions in (Co/Pt)3/(011) Pb(Mg1/3Nb2/3)O3-PbTiO3 multiferroic heterostructures through a voltage-controllable spin reorientation transition (SRT). The SRT onset temperature can be dramatically suppressed at least 200 K by applying an electric field, accompanied by a giant electric-field-induced effective magnetic anisotropy field (ΔHeff) up to 1100 Oe at 100 K. In comparison with conventional strain-mediated magnetoelastic coupling that provides a ΔHeff of only 110 Oe, that enormous effective field is mainly related to the interface effect of electric field modification of spin-orbit coupling from Co/Pt interfacial hybridization via strain. Moreover, electric field control of SRT is also achieved at room temperature, resulting in a ΔHeff of nearly 550 Oe. In addition, ferroelastically nonvolatile switching of PMA has been demonstrated in this system. E-field control of PMA and SRT in multiferroic heterostructures not only provides a platform to study strain effect and interfacial effect on magnetic anisotropy of the ultrathin ferromagnetic films but also enables the realization of power efficient PMA magnetoelectric and spintronic devices.
Collapse
Affiliation(s)
- Bin Peng
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Ziyao Zhou
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Tianxiang Nan
- Department of Electrical and Computer Engineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Guohua Dong
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Mengmeng Feng
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Qu Yang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Xinjun Wang
- Department of Electrical and Computer Engineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Shishun Zhao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Dan Xian
- Collaborative Innovation Center of High-End Manufacturing Equipment, Xi'an Jiaotong University , Xi'an 710049, China
| | - Zhuang-De Jiang
- Collaborative Innovation Center of High-End Manufacturing Equipment, Xi'an Jiaotong University , Xi'an 710049, China
| | - Wei Ren
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
- Collaborative Innovation Center of High-End Manufacturing Equipment, Xi'an Jiaotong University , Xi'an 710049, China
| | - Zuo-Guang Ye
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
- Department of Chemistry and 4D LABS, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
| | - Nian X Sun
- Department of Electrical and Computer Engineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ming Liu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
- Collaborative Innovation Center of High-End Manufacturing Equipment, Xi'an Jiaotong University , Xi'an 710049, China
| |
Collapse
|
8
|
Sun Y, Ba Y, Chen A, He W, Wang W, Zheng X, Zou L, Zhang Y, Yang Q, Yan L, Feng C, Zhang Q, Cai J, Wu W, Liu M, Gu L, Cheng Z, Nan CW, Qiu Z, Wu Y, Li J, Zhao Y. Electric-Field Modulation of Interface Magnetic Anisotropy and Spin Reorientation Transition in (Co/Pt) 3/PMN-PT Heterostructure. ACS APPLIED MATERIALS & INTERFACES 2017; 9:10855-10864. [PMID: 28266829 DOI: 10.1021/acsami.7b00284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report electric-field control of magnetism of (Co/Pt)3 multilayers involving perpendicular magnetic anisotropy with different Co-layer thicknesses grown on Pb(Mg,Nb)O3-PbTiO3 (PMN-PT) FE substrates. For the first time, electric-field control of the interface magnetic anisotropy, which results in the spin reorientation transition, was demonstrated. The electric-field-induced changes of the bulk and interface magnetic anisotropies can be understood by considering the strain-induced change of magnetoelastic energy and weakening of Pt 5d-Co 3d hybridization, respectively. We also demonstrate the role of competition between the applied magnetic field and the electric field in determining the magnetization of the sample with the coexistence phase. Our results demonstrate electric-field control of magnetism by harnessing the strain-mediated coupling in multiferroic heterostructures with perpendicular magnetic anisotropy and are helpful for electric-field modulations of Dzyaloshinskii-Moriya interaction and Rashba effect at interfaces to engineer new functionalities.
Collapse
Affiliation(s)
- Ying Sun
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - You Ba
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Aitian Chen
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Wei He
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Wenbo Wang
- Department of Physics and Astronomy, Rutgers University , Piscataway, New Jersey 08854, United States
| | - Xiaoli Zheng
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Lvkuan Zou
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Yijun Zhang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Qu Yang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Lingjia Yan
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Ce Feng
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Weida Wu
- Department of Physics and Astronomy, Rutgers University , Piscataway, New Jersey 08854, United States
| | - Ming Liu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University , Xi'an 710049, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Zhaohua Cheng
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | | | - Ziqiang Qiu
- Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States
| | - Yizheng Wu
- Department of Physics, State Key Laboratory of Surface Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China
| | - Jia Li
- International Center for Quantum Materials, School of Physics, Peking University , Beijing 100871, China
| | - Yonggang Zhao
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| |
Collapse
|
9
|
Vu AD, Coraux J, Chen G, N'Diaye AT, Schmid AK, Rougemaille N. Unconventional magnetisation texture in graphene/cobalt hybrids. Sci Rep 2016; 6:24783. [PMID: 27114039 PMCID: PMC4844999 DOI: 10.1038/srep24783] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 04/06/2016] [Indexed: 11/15/2022] Open
Abstract
Magnetic domain structure and spin-dependent reflectivity measurements on cobalt thin films intercalated at the graphene/Ir(111) interface are investigated using spin-polarised low-energy electron microscopy. We find that graphene-covered cobalt films have surprising magnetic properties. Vectorial imaging of magnetic domains reveals an unusually gradual thickness-dependent spin reorientation transition, in which magnetisation rotates from out-of-the-film plane to the in-plane direction by less than 10° per cobalt monolayer. During this transition, cobalt films have a meandering spin texture, characterised by a complex, three-dimensional, wavy magnetisation pattern. In addition, spectroscopy measurements suggest that the electronic band structure of the unoccupied states is essentially spin-independent already a few electron-Volts above the vacuum level. These properties strikingly differ from those of pristine cobalt films and could open new prospects in surface magnetism.
Collapse
Affiliation(s)
- A D Vu
- CNRS, Inst NEEL, F-38000 Grenoble, France.,Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble, France
| | - J Coraux
- CNRS, Inst NEEL, F-38000 Grenoble, France.,Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble, France
| | - G Chen
- NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A K Schmid
- NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - N Rougemaille
- CNRS, Inst NEEL, F-38000 Grenoble, France.,Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble, France
| |
Collapse
|
10
|
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.
Collapse
|
11
|
Dipolar-energy-activated magnetic domain pattern transformation driven by thermal fluctuations. Nat Commun 2013; 4:2054. [PMID: 23784257 DOI: 10.1038/ncomms3054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 05/24/2013] [Indexed: 11/08/2022] Open
Abstract
Two-dimensional ferromagnetic layers can serve as a playground for the study of basic physical properties of various pattern forming systems by virtue of their tuneable magnetic properties. Here we use threshold photoemission magnetic circular dichroism in combination with photoemission electron microscopy to investigate ultra-thin ferromagnetic Fe/Ni/Cu(001) films in the stripe domain phase near the spin reorientation transition as a function of film thickness, temperature and effective anisotropy. Here we report a metastable domain state with domain width larger than the thermodynamically stable one as a result of a rapid reduction of the anisotropy. The transformation into the equilibrium state takes place via the propagation of a transition front, which originates from defined steps in the film thickness.
Collapse
|
12
|
Yin S, Zhong F. Coupling-induced reorientation phase transitions in ultrathin Fe/Gd films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:296008. [PMID: 21399325 DOI: 10.1088/0953-8984/22/29/296008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A phenomenological explanation for the reorientation phase transitions in an Fe/Gd ultrathin film system on the basis of Landau's theory of phase transitions is proposed. We model the film as a strongly coupled bilayer-like system consisting of the surface Fe overlayers and the interfacial Gd layer(s) below them. The total free energy of the system is accordingly obtained and the relevant phases and the order of the phase transitions involved are thus determined. Qualitative accordance between the theory and experiments is obtained. An alternative mechanism is proposed that attributes primarily the observed first-order phase transition in the system to the strong coupling between the Fe and the Gd film and its induced vertical magnetization component of the latter film. Competition between the antiferromagnetic coupling and the anisotropy energy of the Fe-rich ultrathin film is responsible for the other continuous reorientation. The effects of an applied external field including several field-induced first- and second-order phase transitions are predicted for experimental verification of the theory.
Collapse
Affiliation(s)
- Shuai Yin
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, People's Republic of China
| | | |
Collapse
|
13
|
Direct imaging of spin-reorientation transitions in ultrathin Ni films by spin-polarized low-energy electron microscopy. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
14
|
|
15
|
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]
|
16
|
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]
|