Highly Isotropic Magnetoresistance in a Single-Component Molecular Metal [Ni(tmdt)₂]

Abstract

We have measured the electrical resistivity and the magnetoresistance (MR) of the single-component molecular metal [Ni(tmdt)₂] at high magnetic fields. The temperature dependence of the resistivity shows a T² behavior up to 30 K, but this is difficult to explain in terms of the simple Fermi liquid picture. We find a highly isotropic positive MR below 4.2 K which exhibits a metal–insulator behavior. These results are discussed in terms of the Zeeman effect in the presence of spin–orbit coupling on the Ni sites.