Mechanisms for multiferroicity in rare-earth orthoferrites: Role of the Dzyaloshinskii-Moriya interaction
Theoretical Condensed Matter Physics
Final Report Abstract
Goal of this project was the determination of the microscopic mechanisms responsible for the coupling between the magnetic and ferroelectric order parameters in various rare-earth ferrooxides RFeO3 with particular focus on the role of the antisymmetric Dzyaloshinskii-Moriya (DM) interaction. The project was launched as a joint Russian-German project between the RWTH Aachen University and the Kurchatov Institute in Saint Petersburg. In spite of various external challenges (Covid-19 pandemic, long shutdowns of major neutron sources - FRM II since spring 2020, ILL upgrade program until spring 2023, the military conflict in Eastern Europe since 2022) we were able to study in detail HoFeO3, TbFeO3 and YbFeO3 and to some extent also LuFeO3, TmFeO3 and DyFeO3. All single crystals were grown using the flux-melt method. The applied experimental methods included macroscopic magnetization, dilatometry and heat capacity measurements, X-ray powder and Laue single crystal diffraction as well as single crystal elastic and inelastic neutron scattering including polarized neutron diffraction. We obtained the magnetic phase diagrams of HoFeO3 and YbFeO3 as function of temperature and external magnetic fields and compared them with the one of TbFeO3. For a detailed consideration of the energy balance between Heisenberg-exchange (HE) interaction, DM interaction, single ion anisotropy (SIA) and external magnetic fields we calculated the exchange parameters between all magnetic ions of the compounds studied by us and compared them with results from other research groups. The exchange within the Fesubsystem is the strongest one, DM interaction leads to a spin canting, SIA stabilizes the system and the exchange interactions of R-Fe and R-R type yield a change in the energy balances of the systems that causes spin reorientation transitions with very different magnetic phase diagrams for the different rare-earths. Our results show that in HoFeO3 the spin dynamics of the Fe subsystem is not affected by the Ho spin reorientation transition. Instead, we found a new low-symmetry magnetic phase which temperature range coincides with temperatures of a reported large magnetocaloric effect in this compound. These and other results were published in five articles in peer-reviewed journals and one PhD thesis. Rare-earth oxides RFeO3 are promising candidates for modern functional materials. A better understanding of the interplay between their fundamental magnetic and electric properties might allow their usage in future spintronics and energy-saving technologies without the use of electric currents and we hope that our results will contribute to this goal.
Publications
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Elastic and inelastic neutron diffraction in rare-earth orthoferrite HoFeO3; talk on the Seminar of IfK RWTH Aachen, Dec. 15th 2020
A.K. Ovsianikov
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Neutron inelastic scattering study of rare-earth orthoferrite HoFeO3. Journal of Magnetism and Magnetic Materials, 507, 166855.
Ovsyanikov, A.K.; Zobkalo, I.A.; Schmidt, W.; Barilo, S.N.; Guretskii, S.A. & Hutanu, V.
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Structure and exchange interactions in rare earth orthoferrites RFeO3 (R = Ho,Tb,Dy,Yb); talk on MLZ Structure Research Group Meeting, Nov. 10th 2021.
A.K. Ovsianikov
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Breaking the Magnetic Symmetry by Reorientation Transition Near 50 K in Multiferroic Magnetocaloric HoFeO3. IEEE Transactions on Magnetics, 58(2), 1-5.
Ovsianikov, Aleksandr; Thoma, Henrik; Usmanov, Oleg; Brown, Penelope Jane; Chatterji, Tapan; Sazonov, Andrew; Barilo, Sergey; Peters, Lars & Hutanu, Vladimir
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Breaking the magnetic symmetry in the HoFeO3 in an external magnetic field; Joint Annual Report 2021 of the MLZ and FRM II, 66 (2022)
A. Ovsianikov; H. Thoma; O. Usmanov; P. J. Brown; T. Chatterji; A. Sazonov; S. Barilo; L. Peters & V. Hutanu
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Breaking the magnetic symmetry in the HoFeO3 in an external magnetic field; Joint Annual Report 2021 of the MLZ and FRM II, 66 (2022)
A. Ovsianikov; H. Thoma; O. Usmanov; P. J. Brown; T. Chatterji; A. Sazonov; S. Barilo; L. Peters & V. Hutanu
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Crystal Field Parameters and Magnetic Properties Correlations in Rare-earth Orthoferrite HoFeO3. Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques, 16(6), 1041-1047.
Usmanov, O. V.; Ovsianikov, A. K.; Zobkalo, I. A.; Shaykhutdinov, K. A.; Terentjev, K. Yu. & Semenov, S. V.
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Exchange interactions and phase transitions in an external magnetic field in orthoferrites RFeO3 (R = Ho, Tb, Yb); talk on MLZ User Meeting 2022; Dec. 8th 2022
A.K. Ovsianikov
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Inelastic neutron studies and diffraction in magnetic fields of TbFeO3 and YbFeO3. Journal of Magnetism and Magnetic Materials, 563, 170025.
Ovsianikov, A.K.; Usmanov, O.V.; Zobkalo, I.A.; Schmidt, W.; Maity, A.; Hutanu, V.; Ressouche, E.; Shaykhutdinov, K.A.; Yu, Terentjev K.; Semenov, S.V.; Meven, M.; Roth, G. & Peters, L.
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Magnetic phase diagram in rare earth orthoferrite HoFeO3 from single crystal neutron diffraction in external magnetic field; poster on 30th Annual Meeting of the German Crystallographic Society, Munich, March 27-30 2022
A.K. Ovsianikov; I.A. Zobkalo; V. Hutanu; S.N. Barilo; K.A. Shaykhutdinov; T. Chatterji; M. Meven; P.J. Brown; G. Roth & L. Peters
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Magnetic phase diagram of HoFeO3 by neutron diffraction. Journal of Magnetism and Magnetic Materials, 557, 169431.
Ovsianikov, A.K.; Usmanov, O.V.; Zobkalo, I.A.; Hutanu, V.; Barilo, S.N.; Liubachko, N.A.; Shaykhutdinov, K.A.; Terentjev, K. Yu; Semenov, S.V.; Chatterji, T.; Meven, M.; Brown, P.J.; Roth, G.; Peters, L.; Deng, H. & Wu, A.
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Exchange interactions in the iron subsystem in rare-earth orthofferites RFeO3 (R = Ho, Tb); poster on 31st Annual Meeting of the German Crystallographic Society (DGK), Frankfurt am Main, March 27-30 2023
A.K. Ovsianikov; P. Fabrykiewicz; I. A. Zobkalo; W. Schmidt; A. Maity; K.A. Shaykhutdinov; M. Meven & G. Roth
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Magnetic phase diagram of HoFeO3 by neutron diffraction; Joint Annual Report 2022 of MLZ & FRM II, 57 (2023)
A. K. Ovsianikov; I. A. Zobkalo; V. Hutanu; S. N. Barilo; N. A. Liubachko; T. Chatterji; M. Meven; P. J. Brown; G. Roth & L. Peters
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Study of exchange interactions in the single crystal of TbFeO3 by inelastic neutron scattering; Joint Annual Report 2022 of MLZ & FRM II, 60 (2023)
A. K. Ovsianikov; I. A. Zobkalo; A. Maity; M. Meven & G. Roth
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The role of exchange interactions in the formation of the magneticstructure in rare-earth orthoferrites RFeO3 (R = Ho, Tb, Yb); PhD thesis, RWTH AachenUniversity
A.K. Ovsianikov
