Magnetism and transport properties of Hf1-xTaxFe2 and Mn2-xCrxSb

The magnetism and transport properties of Hf1 - xTaxFe2 (0.1 less than or e qual to x less than or equal to 0.2) and Mn2 - xCrxSb (x=0.1) were studied. Hf1 - xTaxFe2 (x>0.15) has a successive magnetic transition from ferromagn etism to paramagnetism via antiferromagnetism at temperatures between 150 a nd 350 K, and the transition has a considerable effect on the transport pro perty. in particular, a specimen with x=0.155 shows a metamagnetic transiti on near room temperature, and a significant magnetoresistance as large as 1 2% is observed in accordance with the metamagnetic transition. Mn1.9Cr0.1Sb , which has a first-order magnetic transition from antiferromagnetism to fe rrimagnetism at about 300 K, also shows a field-induced magnetic transition at 300 K, and the transition strongly affects the transport property. A gi ant magnetoresistance as large as 30% was observed at about 300 K under an applied field of 20 kOe. The metamagnetic transition seems to give rise to giant magnetoresistance via s-d scattering. (C) 1999 Elsevier Science S.A. All rights reserved.