Optical seminar | 16 December 2022

Kirensky Institute of Physics, Federal Research Center KSC SB RAS
Raman spectroscopy study structural and magnetic transitions in crystals RMe(BO3)4 with rare earth elements

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.

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