Transport, Magnetic and Thermal Properties of BaCo_1-xNi_xS₂

Abstract

Physical properties of quasi two-dimensional electrons of BaCo_1-xNi_xS₂ which exhibits the Mott metal-insulator transition are reported. Various anomalous behaviors which are similar to those of high-T_c Cu oxides have been found. It is suggested that these anomalies are induced in the metallic and magnetically correlated state without long range order and therefore with very strong low energy magnetic fluctuations. It remains unclear if the system exhibits a decreasing tendency of the electronic specific heat coefficient γ upon approaching the Mott insulating phase, which is one of the remarkable anomalous behaviors of high-T_c oxides. Superconductivity has not been found down to 1.4, K.