Magnetization study on single-crystalline TbMn₆Ge₆

The compound TbMn₆Ge₆ exhibits unusual magnetic properties. Low-field magnetization measurements show that TbMn ₆Ge₆ orders around 450 K. In the whole ordered range, metamagnetic behavior with appreciable hysteresis is observed, both for the field applied parallel and perpendicular to the crystallographic c-direction. The saturation moment of 5 μ_B/f.u. obtained at temperatures around 300-350 K after the metamagnetic transition that occurs below 1 T suggests collinear ferrimagnetic order of the magnetic Tb and Mn sublattices after the transition. The critical field of the metamagnetic transition increases with decreasing temperature. Also, measurements of the magnetization have been carried out in high magnetic fields up to around 50 T at various temperatures in the ordered region. The magnetic isotherms measured with the field applied along the main crystallographic directions exhibit a wealth of field-induced phase transitions that provide information on the competing interactions in this compound.