1
|
Ngabonziza P, Carleschi E, Zabolotnyy V, Taleb-Ibrahimi A, Bertran F, Fittipaldi R, Granata V, Cuoco M, Vecchione A, Doyle BP. Fermi surface and kink structures in [Formula: see text] revealed by synchrotron-based ARPES. Sci Rep 2020; 10:21062. [PMID: 33273484 PMCID: PMC7712785 DOI: 10.1038/s41598-020-77845-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/13/2020] [Indexed: 11/08/2022] Open
Abstract
The low-energy electronic structure, including the Fermi surface topology, of the itinerant metamagnet [Formula: see text] is investigated for the first time by synchrotron-based angle-resolved photoemission. Well-defined quasiparticle band dispersions with matrix element dependencies on photon energy or photon polarization are presented. Four bands crossing the Fermi-level, giving rise to four Fermi surface sheets are resolved; and their complete topography, effective mass as well as their electron and hole character are determined. These data reveal the presence of kink structures in the near-Fermi-level band dispersion, with energies ranging from 30 to 69 meV. Together with previously reported Raman spectroscopy and lattice dynamic calculation studies, the data suggest that these kinks originate from strong electron-phonon coupling present in [Formula: see text]. Considering that the kink structures of [Formula: see text] are similar to those of the other three members of the Ruddlesden Popper structured ruthenates, the possible universality of strong coupling of electrons to oxygen-related phonons in [Formula: see text] compounds is proposed.
Collapse
Affiliation(s)
- Prosper Ngabonziza
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
- Department of Physics, University of Johannesburg, PO Box 524, Auckland Park
, 2006 South Africa
| | - Emanuela Carleschi
- Department of Physics, University of Johannesburg, PO Box 524, Auckland Park
, 2006 South Africa
| | - Volodymyr Zabolotnyy
- Physikalisches Institut, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Amina Taleb-Ibrahimi
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - François Bertran
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - Rosalba Fittipaldi
- CNR-SPIN Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Veronica Granata
- CNR-SPIN Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Mario Cuoco
- CNR-SPIN Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Antonio Vecchione
- CNR-SPIN Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Bryan Patrick Doyle
- Department of Physics, University of Johannesburg, PO Box 524, Auckland Park
, 2006 South Africa
| |
Collapse
|
2
|
Anisotropic and nonlinear magnetodielectric effects in orthoferrite ErFeO 3 single crystals. Sci Rep 2020; 10:11825. [PMID: 32678242 PMCID: PMC7367349 DOI: 10.1038/s41598-020-68800-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/24/2020] [Indexed: 11/20/2022] Open
Abstract
In rare-earth orthoferrites, strongly correlated order parameters have been thoroughly investigated, which aims to find multiple functionalities such as multiferroic or magnetoelectric properties. We have discovered highly anisotropic and nonlinear magnetodielectric effects from detailed measurements of magnetoelectric properties in single-crystalline orthoferrite, ErFeO3. Isothermal dielectric constant varies in shapes and signs depending on the relative orientations between the external electric and magnetic fields, which may be ascribed to the spin-phonon couplings. In addition, a dielectric constant with both electric and magnetic fields along the c axis exhibits two symmetric sharp anomalies, which are closely relevant to the spin-flop transition, below the ordering temperature of Er3+ spins, TEr = 3.4 K. We speculate that the magnetostriction from the exchange couplings between Er3+ and Fe3+ magnetic moments would be responsible for this relationship between electric and magnetic properties. Our results present significant characteristics of the orthoferrite compounds and offer a crucial guide for exploring suitable materials for magnetoelectric functional applications.
Collapse
|
3
|
Jeong SG, Lim SY, Kim J, Park S, Cheong H, Choi WS. Spin-phonon coupling in epitaxial SrRuO 3 heterostructures. NANOSCALE 2020; 12:13926-13932. [PMID: 32608441 DOI: 10.1039/d0nr03282d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spin-phonon coupling is one of the fundamental interactions in functional materials, indispensable for understanding their unexpected magnetic ground states. Ferromagnetic SrRuO3 is a correlated metal with the potential for utilization in novel spintronic devices and serves as a promising platform for studying spin-phonon interactions. In this study, we used Raman spectroscopy to identify spin-phonon coupling in SrRuO3 heterostructures. We deliberately decreased the exchange interactions within SrRuO3 by reducing system dimensions, which was coherently observed in both temperature-dependent magnetization measurements and phonon spectra. To collect the Raman signals from the very thin (quasi-2D) SrRuO3 layers while maintaining the layer thickness, we fabricated epitaxial oxide superlattices with 50 repetitions of the layers. We also present polarization-dependent Raman spectra of SrRuO3, with accurate identification of the Raman modes. These results show that the phonon dynamics of SrRuO3 is strongly influenced by the spin ordering, which can be efficiently tailored via atomically controlled epitaxial heterostructuring.
Collapse
Affiliation(s)
- Seung Gyo Jeong
- Department of Physics, Sungkyunkwan University, Suwon 16419, Korea.
| | | | | | | | | | | |
Collapse
|
4
|
Mishra KK, Shukla R, Krishna PSR, Babu PD, Achary SN, Katiyar RS, Scott JF. Phonon and magnetoelastic coupling in Al 0.5Ga 0.5FeO 3: Raman, magnetization and neutron diffraction studies. Phys Chem Chem Phys 2020; 22:6906-6918. [PMID: 32181452 DOI: 10.1039/c9cp06124j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The intriguing coupling phenomena among spin, phonon, and charge degrees of freedom in materials having magnetic, ferroelectric and/or ferroelastic order have been of research interest for the fundamental understanding and technological relevance. We report a detailed study on structure and phonons of Al0.5Ga0.5FeO3 (ALGF), a lead-free magnetoelectric material, carried out using variable temperature dependent powder neutron diffraction and Raman spectroscopy. Neutron diffraction studies suggest that Al3+ ions are distributed in one tetrahedrally (BO4) and three octahedrally (BO6) coordinated sites of the orthorhombic (Pc21n) structure and there is no structural transition in the temperature range of 7-800 K. Temperature dependent field-cooled and zero-field-cooled magnetization studies indicate ferrimagnetic ordering below 225 K (TN), and that is reflected in the low temperature powder neutron diffraction data. An antiferromagnetic type arrangement of Fe3+ ions with net magnetic moment of 0.13 μB/Fe3+ was observed from powder neutron diffraction analysis and it corroborates the findings from magnetization studies. At the magnetic transition temperature, no drastic change in lattice strain was observed, while significant changes in phonons were observed in the Raman spectra. The deviation of several mode frequencies from the standard anharmonicity model in the ferrimagnetic phase (below 240 K) is attributed to coupling effect between spin and phonon. Spin-phonon coupling effect is discernable from Raman bands located at 270, 425, 582, 695, 738, and 841 cm-1. Their coupling strengths (λ) have been estimated using our phonon spectra and magnetization results. BOn (n = 4, 6) libration (restricted rotation) mode at 270 cm-1 has the largest coupling constant (λ∼ 2.3), while the stretching vibrations located at 695 and 738 cm-1 have the lowest coupling constant (λ∼ 0.5). In addition to the libration mode, several internal stretching and bending modes of polyhedral units are strongly affected by spin ordering.
Collapse
Affiliation(s)
- K K Mishra
- Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, P.O. Box 70377, San Juan, PR 00936-8377, USA.
| | | | | | | | | | | | | |
Collapse
|
5
|
Zhu M, Li PG, Wang Y, Cao HB, Tian W, Zhang HD, Phelan BD, Mao ZQ, Ke X. Temperature- and field-driven spin reorientations in triple-layer ruthenate Sr 4Ru 3O 10. Sci Rep 2018; 8:3914. [PMID: 29500391 PMCID: PMC5834612 DOI: 10.1038/s41598-018-22247-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/20/2018] [Indexed: 11/10/2022] Open
Abstract
Sr4Ru3O10, the n = 3 member of the Ruddlesden-Popper type ruthenate Srn+1RunO3n+1, is known to exhibit a peculiar metamagnetic transition in an in-plane magnetic field. However, the nature of both the temperature- and field-dependent phase transitions remains as a topic of debate. Here, we have investigated the magnetic transitions of Sr4Ru3O10 via single-crystal neutron diffraction measurements. At zero field, we find that the system undergoes a ferromagnetic transition with both in-plane and out-of-plane magnetic components at Tc ≈ 100 K. Below T * = 50 K, the magnetic moments incline continuously toward the out-of-plane direction. At T = 1.5 K, where the spins are nearly aligned along the c axis, a spin reorientation occurs above a critical field Bc, giving rise to a spin component perpendicular to the plane defined by the field direction and the c axis. We suggest that both the temperature- and field-driven spin reorientations are associated with a change in the magnetocrystalline anisotropy, which is strongly coupled to the lattice degrees of freedom. This study elucidates the long-standing puzzles on the zero-field magnetic orders of Sr4Ru3O10 and provides new insights into the nature of the field-induced metamagnetic transition.
Collapse
Affiliation(s)
- M Zhu
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, 48824, USA
| | - P G Li
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana, 70118, USA
| | - Y Wang
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana, 70118, USA
| | - H B Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - W Tian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - H D Zhang
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, 48824, USA
| | - B D Phelan
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Z Q Mao
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana, 70118, USA
| | - X Ke
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, 48824, USA.
| |
Collapse
|
6
|
Abstract
Metamagnetism occuring inside a ferromagnetic phase is peculiar. Therefore, Sr4Ru3O10, a TC = 105 K ferromagnet, has attracted much attention in recent years, because it develops a pronounced metamagnetic anomaly below TC for magnetic fields applied in the crystallographic ab-plane. The metamagnetic transition moves to higher fields for lower temperatures and splits into a double anomaly at critical fields Hc1 = 2.3 T and Hc2 = 2.8 T, respectively. Here, we report a detailed study of the different components of the magnetization vector as a function of temperature, applied magnetic field, and varying angle in Sr4Ru3O10. We discover for the first time a reduction of the magnetic moment in the plane of rotation at the metamagnetic transition. The anomaly shifts to higher fields by rotating the field from H ⊥ c to H || c. We compare our experimental findings with numerical simulations based on spin reorientation models taking into account magnetocrystalline anisotropy, Zeeman effect and antisymmetric exchange interactions. While Magnetocrystalline anisotropy combined with a Zeeman term are sufficient to explain a metamagnetic transition in Sr4Ru3O10, a Dzyaloshinskii-Moriya term is crucial to account for the reduction of the magnetic moment as observed in the experiments.
Collapse
|
7
|
Musfeldt JL, Brinzari TV, Schlueter JA, Manson JL, Litvinchuk AP, Liu Z. Pressure-induced local lattice distortions in α-Co[N(CN)2]2. Inorg Chem 2013; 52:14148-54. [PMID: 24299233 DOI: 10.1021/ic402010h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work brings together diamond anvil cell techniques, vibrational spectroscopies, and complementary lattice dynamics calculations to investigate pressure-induced local lattice distortions in α-Co[N(CN)2]2. Analysis of mode behavior and displacement patterns reveals a series of pressure-driven transitions that modify the CoN6 counter-rotations, distort the octahedra, and flatten the C-N(ax)-C linkages. These local lattice distortions may be responsible for the low temperature magnetic crossover. We also discuss prospects for negative thermal expansion and show that there is not a straightforward low pressure pathway between the pink α and blue β ambient pressure phases of Co[N(CN)2]2.
Collapse
Affiliation(s)
- J L Musfeldt
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | | | | | | | | | | |
Collapse
|
8
|
Granata V, Capogna L, Reehuis M, Fittipaldi R, Ouladdiaf B, Pace S, Cuoco M, Vecchione A. Neutron diffraction study of triple-layered Sr4Ru3O10. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:056004. [PMID: 23286951 DOI: 10.1088/0953-8984/25/5/056004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The magnetic properties of the triple-layered Sr(4)Ru(3)O(10) have been investigated by means of neutron scattering diffraction. At zero field we find that the magnetic moments are ferromagnetically coupled and oriented along the c-axis with no signatures of either long-range antiferromagnetic order or ferromagnetic components in the ab-plane. The field dependence of the reflection intensity points to a metamagnetic response involving only the planar magnetic moments. The structural refinement indicates a distinct rearrangement of the unit cell as a function of both temperature and in-plane applied field. We show that at the temperature T* ~/= 50 K, below which the metamagnetic behavior is observed, the c-axis lattice parameter exhibits a rapid increase while the in-plane amplitude saturates. A similar upturn of the in-plane lattice parameter after the quench of the c-axis amplitude occurs above a critical magnetic field.
Collapse
|
9
|
Mukherjee S, Garg A, Gupta R. Probing magnetoelastic coupling and structural changes in magnetoelectric gallium ferrite. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:445403. [PMID: 22012703 DOI: 10.1088/0953-8984/23/44/445403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Temperature dependent x-ray diffraction and Raman spectroscopic studies were carried out on flux-grown single crystals of gallium ferrite with a Ga:Fe ratio of 0.9:1.1. Site occupancy calculations from the Rietveld refinement of the x-ray data led to an estimated magnetic moment of ~0.60 μ(B)/f.u. which was in good agreement with the experimental data. A combination of these two measurements indicates that there is no structural phase transition in the material between 18 and 700 K. A detailed line shape analysis of the Raman mode at ~374 cm(-1) revealed a discontinuity in the peak position data indicating the presence of spin-phonon coupling in gallium ferrite. A correlation of the peak frequency with the magnetization data led to two distinct regions across a temperature ~180 K with appreciable change in the spin-phonon coupling strength from ~0.9 (T < 180 K) to 0.12 cm(-1) (180 K < T < T(c)). This abrupt change in the coupling strength at ~180 K strongly suggests an altered spin dynamics across this temperature.
Collapse
Affiliation(s)
- Somdutta Mukherjee
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208106, India
| | | | | |
Collapse
|
10
|
Musfeldt JL, Liu Z, Li S, Kang J, Lee C, Jena P, Manson JL, Schlueter JA, Carr GL, Whangbo MH. Pressure-Induced Local Structure Distortions in Cu(pyz)F2(H2O)2. Inorg Chem 2011; 50:6347-52. [PMID: 21644536 DOI: 10.1021/ic2008039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. L. Musfeldt
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Z. Liu
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, United States
| | - S. Li
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - J. Kang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - C. Lee
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - P. Jena
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - J. L. Manson
- Department of Chemistry, and Biochemistry, Eastern Washington University, Cheney, Washington 99004, United States
| | - J. A. Schlueter
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - G. L. Carr
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - M.-H. Whangbo
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| |
Collapse
|
11
|
Musfeldt JL, Vergara LI, Brinzari TV, Lee C, Tung LC, Kang J, Wang YJ, Schlueter JA, Manson JL, Whangbo MH. Magnetoelastic coupling through the antiferromagnet-to-ferromagnet transition of quasi-two-dimensional [Cu(HF2)(pyz)2]BF4 using infrared spectroscopy. PHYSICAL REVIEW LETTERS 2009; 103:157401. [PMID: 19905665 DOI: 10.1103/physrevlett.103.157401] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Indexed: 05/28/2023]
Abstract
We investigated magnetoelastic coupling through the field-driven transition to the fully polarized magnetic state in quasi-two-dimensional [Cu(HF2)(pyz)2]BF4 by magnetoinfrared spectroscopy. This transition modifies out-of-plane ring distortion and bending vibrational modes of the pyrazine ligand. The extent of these distortions increases with the field, systematically tracking the low-temperature magnetization. These distortions weaken the antiferromagnetic spin exchange, a finding that provides important insight into magnetic transitions in other copper halides.
Collapse
Affiliation(s)
- J L Musfeldt
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|