Pressure Effect on Metal/Insulator Transition in Y1-xCaxTiO3

The magnetic susceptibility and electrical resistivity in the metal-insulator (MI) transition of a mixed-valent Ti-oxide system, Y1-x CaxRTiO3, is investigated as a function of pressure. This system exhibits obviously the temperatureinduced MI transition at x=0. 3-0. 4. At the low temperature metallic phase, susceptibility, X (T), is strongly suppressed with pressure. On the other hand, in the high temperature semiconductiong phase X (T) obeying the Curie-Weiss law is not affected strongly with pressure. The coefficient of the T2-term in resistivity, A, and the residual resistivity, ρ (0), are decreases rapidly with pressure. At x=0. 375 and 0. 39, we recognize the relation of A∝X (10 K) 2 at the low temperature metallic state.