New Magnetoresistance Results in GdB6

Abstract

Detailed study of transverse magnetoresistance (MR) and magnetic susceptibility have been done on the high quality single crystals of antiferromagnet GdB6 (TN15.5K) in the wide range of temperatures 2-40K in magnetic fields up to 8T. The data obtained allow to establish the low temperature antiferromagnetic (AFMII) phase below T*~4.7K with the complex behavior of MR including the field hysteresis of the magnetoresistance. It was shown that MR behavior depends on the cooling-warming prehistory in AFM state of GdB6. The analysis of experimental data allowed us to deduce three contributions to MR in AFM(I), (T*) and paramagnetic (PM) phases of GdB6. In addition to the main negative component Δρ˿ρ~ H2 interpreted in terms of Yosida model both the linear and nonlinear magnetic contributions were also established. The anomalies of MR found in AFM(I) state seem to be associated with the local spin polarization of 5d-electron states of Gd3+ ion.