Anomalous magnetoresistance near the spin reorientation transition of dilute Gd–Y single crystals

Abstract

We report very detailed measurements of the magnetoresistance (MR) in the vicinity (±5 K) of the spin reorientation temperature ( T SR ) for pure Gd and Gd 1− x Y x single crystals with x =0.025 and 0.075. The temperature dependence of the a- axis magnetoresistance in pure Gd is always negative in the temperature range studied. In the dilute Gd–Y samples the low-field MR changes from negative above T SR to positive for T < T SR , becoming again negative below some lower temperature T * , where another phase transition takes place.