Magnetostructural phase transformations in Tb1−xMn2

Abstract

Magnetism and phase transformations in non-stoichiometric Tb_1−xMn₂ (x = 0.056, 0.039) have been studied as functions of temperature and magnetic field using magnetization, heat capacity, and X-ray powder diffraction measurements. Upon lowering the temperature, the compounds sequentially order ferrimagnetically and antiferromagnetically, and finally, exhibit spin reorientation transitions. Structural distortions from room temperature cubic to low temperature rhombohedral structures occur at T_N, and are accompanied by large volume changes reaching ∼−1.27% and −1.42%, respectively. First principles electronic structure calculations confirm the phase transformation from the ferrimagnetic cubic structure to the antiferromagnetic rhombohedral structure in TbMn₂.