Doping effects on structure, morphology and magnetic properties of SmFe1−xMnxO3 nanopowders

The ReFeO₃ (where Re is rare earth element) materials crystallize in a distorted perovskite structure with an orthorhombic unit cell. They exhibit a large number of novel and interesting physical phenomena, including magneto-optic effects, colossal magnetoresistance, high-Tc superconductivity, and multiferroic behaviors[1, 2]. These materials have widely potential applications in various fields, such as catalysts[3], solid oxide fuel cells[4], gas sensors[5], microwave absorbing materials[6], semiconductors[7], and magneto-optic materials[8]. Among the family of ReFeO₃, SmFeO₃ exhibits G-type antiferromagnetic ordering below T_N=670K and an easy axis rotation transition (spin reorientation transition, SR) from c-axis to a-axis, which occurs at a quite high temperature T_SR=480K. Lee et al. reported that the canted antiferromagnetic ordering causes extraordinary polarization in SmFeO₃ and spontaneous magnetization reversal at cryogenic temperatures. This reversal is attributed to the activation of the Sm magnetism (4f-electrons), which is antiparallel to the Fe (3d-electrons).