Magnetotransport Properties of Heavy-Fermion Ferromagnet YbPtGe

Abstract

The transverse magnetoresistivity ρ H , Hall coefficient R H , and specific heat C for H ∥ a below 10 kOe for the moderate heavy-fermion ferromagnet YbPtGe with the Curie-temperature T C =5.4 K are reported. It is observed that the ρ H ( T ) values for the currents along the three crystallographic axes markedly decrease below 30 K with increasing applied magnetic field up to 90 kOe. Below T C , ρ H ( H ) at low fields show peak structures for H ∥ a and H ∥ b , and a shoulder for H ∥ c , the positions of which correspond to those of shoulders that observed in the field dependence of the magnetization. The sharp peak of C ( T ) due to magnetic transition decays and shifts to the low-temperature side with increasing field for H ∥ a up to 3 kOe. The H – T phase diagram below T C is proposed from those measurements. In addition, R H ( T ) for I ∥ b and H ∥ c at 10 kOe increases from a value close to the expected Hall coefficient for a carrier concentration of 1 hole/f.u. with decreasing temperature from 300 K,...