Evidence of ferromagnetic quantum phase transition in Ba1-xSrxVS3

Resistivity under pressure and magnetization measurements on Ba1-xSrxVS3 single crystals with 0 x 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 BaVS3. The 0.07 < x results suggest a coexistence of FM and metallic phases at larger x.