Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2008; 53(2): 758-762

Published online August 14, 2008

Copyright © The Korean Physical Society.

Magnetic Properties of the Orthoferrites TbFeO3 and ErFeO3

Byeong-Gyu Park, Sung Baek Kim, Hyo-Jin Lee, Yoon Hee Jeong, Jae-Hoon Park and Chul-Sung Kim


The magnetic properties of the single-crystalline orthoferrites TbFeO$_3$ and ErFeO$_3$ were investigated by using a vibrating sample magnetometer (VSM). Both ferrites exhibit weak ferromagnetism with the maximum saturated moment being 0.125 and 0.054 $mu_B$/Fe for TbFeO$_3$ and ErFeO$_3$, respectively. We confirmed the spin reorientation transition (SRT) in both systems. These two ferrites display different temperature-dependent behaviors of the magnetization, which we analyzed within the molecular field model. The results suggest that the Fe 3$d$-Er 4$f$ magnetic coupling through the molecular field of the ordered Fe net moment is unexpectedly antiferromagnetism, opposite to the ferromagnetic Fe 3$d$-Tb 4$f$ coupling. Further, the coupling widely varies with temperature and/or with the SRT, indicating that the Tb/Er moment is not simply explained by the partial polarization of the paramagnetic spins experiencing the molecular field of the net Fe moment.

Keywords: Rare-earth orthoferrite, Canted antiferromagnet, Weak ferromagnetism