METAL-INSULATOR TRANSITIONS AND WEAK FERROMAGNETISM IN THE ELECTRON-CORRELATED SYSTEM ND1-XCAXTIO3 (0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1)

The transport and magnetic properties of a series of Nd1-xCaxTiO3 perovskites where 0 less-than-or-equal-to x less-than-or-equal-to 0.8 were investigated. The transition from a Mott-Hubbard insulator (NdTiO3) with a 3d1 configuration to a metallic state was observed to take place near x = 0.15. Low-field susceptibility and remanent-moment measurements suggest that Nd1-xCaxTiO3 orders antiferromagnetically in the composition region 0 less-than-or-equal-to x less than or similar to 0.15. The metallic Nd1-xCaxTiO3 compounds behave as Fermi-liquid systems where the. effective mass increases as the metal-insulator boundary (x almost-equal-to 0.15) is approached.