2024/07/29 by Shantanu Mukherjee, Mukherjee, S., Oleh Ivashko +7
Physics and Astronomy · Materials Science · #Advanced Condensed Matter Physics #Nuclear materials and radiation effects #Multiferroics and related materials
paper · doi:10.48550/arxiv.2407.19883
Sm2Ti2O7, a member of rare-earth titanate pyrochlores, exhibits dipolar-octupolar antiferromagnetism below TN = 0.35 K. We observed two ferroelectric transitions at 182 (TFE1) and 52 K (TFE2), significantly higher than TN for Sm2Ti2-xVxO7 (x = 0, 0.1). Although the ferroelectric transition temperatures remain unchanged, the polarization value decreases considerably with V doping. A structural transition to a polar R3m rhombohedral phase from the cubic Fd3m structure occurs at TFE1, involving a distortion in the pyochlore lattice. Remarkably, significant linear magnetoelectric coupling is observed in both compounds, with further enhancement of magnetoelectric coupling due to magnetic V doping. The existence of magnetoelectric coupling without long-range magnetic order in a frustrated pyrochlore system could enable the tailoring of magnetoelectric coupling properties, which can be further fine-tuned through V doping. The emergence of ferroelectricity in a frustrated magnetic system introduces an intriguing aspect to these compounds and paves the way for developing ferroelectric order driven by the alleviation of magnetic frustration in pyrochlore systems.