Spontaneous and Field-Induced magnetic Phase Transitions in Tb_(1-x)R_xMn_6Sn_6 (R = Gd, Y) Compounds

摘要

Magnetization curves and magnetic susceptibility of Tb_(1-x)R_xMn_6Sn_6 (R = Gd, Y) compounds have been measured for aligned powder samples. Concentration dependences of the spin-reorientation transition temperature and temperature dependences of cri tical fields of the field-induced magnetic transitions have been determined. For the compound Tb_(0.1)Y_(0.9)Mn_6Sn_6 with the spiral magnetic structure, we found that application of hydrostatic pressure facilitates the ferrimagnetic ordering. This unusual feature is supported by the observation of a large negative spontaneous volume magnetostriction for TbMn_6Sn_6. The obtained results are discussed in a model considering three different interlayer Mn-Mn exchange interactions in these compounds.