Strong Pressure Effect on the Electrical Resistivity of BaCo1-xNixS2

Electrical resistivities ρ of BaCo 1- x Ni x S 2 , which has a layered structure and exhibits the Mott transition with varying x , have been found to be strongly sensitive to pressure over a very wide temperature region. The paramagnetic insulator state, which exists in the region of \(x0.15\) above the Néel temperature T N , exhibits a transition to a metallic state at a rather small value of applied pressure p . The temperature T N , at which the resistivity ρ exhibits anomalous increase with decreasing T , rapidly decreases with increasing p and becomes zero at the critical value of p = p c ( x ) (\(15\,\)kbar for x ≥0.05). The paramagnetic state thus obtained exhibits roughly T 2 -like dependence of the resistivity. The metal-insulator transition of the present system is known to be easily controlled by the external pressure.