Structural and electrical properties evolution in Ba_1-xSr_xRuO₃ synthesized under high pressure

The 6H and 6M Ba_1-xSr_xRuO₃ at x≤0.6 with the normal and distorted hexagonal BaTiO₃ structures were synthesized by using high-pressure and high-temperature method. It is found that the unit cell volume deviates from Vegard's law between 0.3 and 0.4 for the solid solutions due to the increasing distortion degree of crystal structure. With the increasing x, the electrical resistivity at the same temperature is increasing. With the substitution of Sr for Ba ion, the 6H BaRuO₃ transforms to a Fermi-liquid metal at x=0.25 from the primal non-Fermi-liquid metal, and then becomes a semiconductor at low temperature when x is larger than 0.4.