Evidence of ferromagnetic quantum phase transition in Ba${}_{1-x}$Sr${}_x$VS${}_3$

Abstract

Resistivity under pressure and magnetization measurements on Ba${}_{1-x}$Sr${}_x$VS${}_3$ single crystals with 0 $\le x\le$ 0.18 and no sulphur deficiency show an abrupt onset of ferromagnetic (FM) order at a critical value $x$=0.07, concomitant to a change of the magnetic properties at the metal-insulator transition (MIT) and to a collapse of the unit cell at ambient temperature. A reduction of the MIT temperature to 50 K upon $x$ that scales as the V-S distance is also observed. This gives evidence of a chemical pressure induced quantum phase transition that stabilizes the incipient FM order of BaVS${}_3$. The $0.07<x$ results suggest a coexistence of FM and metallic phases at larger $x$.

4 pages 5 figures