Physical properties and anisotropies of the RNiGe 3 series ( R = Y, Ce–Nd, Sm, Gd–Lu)

Abstract

We have studied RNiGe 3 ( R=Y, Ce–Nd, Sm, Gd–Lu) single crystals by measuring crystal structure and stoichiometry, magnetic susceptibility, magnetization, electrical resistivity, magnetoresistance, and specific heat. Clear anisotropies as well as antiferromagnetic ordering in the RNiGe 3 series ( R=Ce–Nd, Sm, Gd–Tm) have been observed above 1.8 K from the magnetic susceptibility. A metamagnetic transition in this family (except for R=Sm) was detected at 2 K for applied magnetic fields below 70 kOe. The electrical resistivity of this series follows metallic behavior in the high temperature region. Below the antiferromagnetic ordering temperature a significant anisotropy is exhibited in the resistivity and magnetoresistance for different current directions. The anisotropic magnetic, transport, and thermal properties of RNiGe 3 compounds are discussed in terms of Ni site occupancy as well as a combination of the effect of formation of a magnetic superzone gap and the crystalline electric field.