Optical seminar | 16 December 2022

Multiferroic materials showing the coexistence of at least two ferroic orders ((anti)ferroelectric, (anti)ferromagnetic and (anti)ferroelastic) are expected to find potential applications in many devices. Amongst these properties, the coexistence of ferroelectricity and ferromagnetism is highly desired. Besides their coexistence, of utmost importance is a strong coupling between the two ferroic orders. In multiferroic materials, the coupling interaction between the different order parameters can produce additional functionalities. The application of multiferroics will make possible to significantly enlarge the functional possibilities of spintronics.
Crystals of the RMe3(BO3)4 family (R is rare earth ion) were reported to possess multiferroic features, demonstrating both structural and magnetic phase transitions, where transition points may be varied by rare earth composition. We used Raman spectroscopy to study single crystals RMe3(BO3)4 (R = Ho, Nd, Tb, Sm, La; M = Fe, Ga, ).
Temperature measurements were performed in the temperature range 10–400 K. High-pressure investigation was carried up to pressure 12 GPa. The aim of this study is to investigate the possible existence of a soft mode related to structural order parameter and effects of magnetic transitions on Raman spectra. Phase diagrams Composition–Temperature as well as Pressure-temperature are presented.

Main paper/arXiv, related to the seminar, and other references

1. Krylov A., Pavlovskiy M., Kitaev Yu., Gudim I., Andryshin N., Vtyurin A., Qinghui Jiang Qinghui, Krylova S. Phase transitions and p–T phase diagram of the multiferroic TbFe3(BO3)4 crystal // J. Raman Spectrosc. — 2022. — V. 53. — 1179-1187
2. Moshkina E., Krylova S., Gudim I., Molokeev M., Temerov V., Pavlovskii M., Vtyurin A., Krylov A. Gallium composition-dependent structural phase transitions in HoFe3-xGax(BO3)4 solid solutions: crystal growth, structure and Raman spectroscopy study // Crystal Growth & Design. — 2020. —V. 20. — 1058-1069.
3. Moshkina E., Gudim I., Temerov V., Krylov A. Temperature‐dependent absorption lines observation in Raman spectra of SmFe3(BO3)4 ferroborate // J. Raman Spec. — 2018. — V. 49. — P. 1732—1735.
4. Krylov A.S., Gudim I.A., Nemtsev I., Krylova S.N., Shabanov A.V., Krylov A.A. Raman study of HoFe3(BO3)4 at simultaneously high pressure and high temperature: p–T phase diagram // J. Raman Spec. 2017. V. 48. P. 1406–1410.
5. Moshkina E, Krylov A, Sofronova S, Gudim I, Temerov V Crystal Growth and Raman Spectroscopy Study of Sm1−xLaxFe3(BO3)4 Ferroborates // Cryst. Growth Des. 2016. V. 16. P. 6915-6921.