Large magnetovolume effects due to transition from the ferromagnetic to antiferromagnetic state in Hf0.825Ta0.175Fe2 intermetallic compound
Résumé
Intrinsic magnetic properties and magnetovolume effects have been investigated for the Hf0.825Ta0.175Fe2 itinerant-electron system, which exhibits a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state. The spontaneous volume magnetostriction contraction due to this transition from the high-volume FM state to the low-volume AFM state is about 0.66%. Applying a magnetic field increases significantly the FM-AFM transition temperature TFM-AFM, with a rate of 7.2 K T-1. At temperatures T > TFM-AFM a first-order metamagnetic transition between the AFM and FM states has been observed from isothermal magnetization curves, a result attributed to the itinerant-electron character of the Fe magnetism. This AFM-FM transition is accompanied by a huge field-induced volume magnetostriction. The change in Delta V/V due to the AFM-FM transition is about 0.75%.