Chemical pressure-induced ferromagnetism and stabilization of the metallic state in Ba/sub 1-x/Sr/sub x/VS/sub 3/

Measurements of magnetization and of resistivity under pressure on Ba/sub 1-x/Sr/sub x/VS/sub 3/ single crystals show that Sr-induced chemical pressure progressively weakens the antiferromagnetic correlations responsible for the metal-insulator transition. The antiferromagnetic ordering temperature, T/sub X/ = 30 K at x = 0, vanishes at x = 0.08. At larger x, a ferromagnetic order appears with T/sub C/ = 21.5 K at x = 0.18. The key-parameter favoring the metallic state is found to be the compression of the VS/sub 6/ octahedra and we predict a metallic state at 0 K for a V-S distance of 2.33 AA. The stabilization effect of the metallic state provided by the chemical pressure is supported by first principles band structure calculations performed by using the Vienna ab initio simulation package (VASP) within the projector augmented-wave (PAW) method in the local density approximation (LDA) + U scheme.