Structural, electronic, and magnetic characterization of the perovskite LaNi1-xTixO3 (O <= x <= 1/2)

Structural, electronic, and magnetic behavior of the LaNi1-xTixO3 (0 less t han or equal to x less than or equal to 1/2) perovskite-like system is repo rted. These phases can be regarded as derived from LaNiO3 by partial substi tution of Ni3+ by Ti4+ cations that produces a partial reduction of Ni3+ to Ni2+. X-ray powder diffraction data were analyzed by the Rietveld method, and rhombohedral (S.G. R (3) over bar c) or orthorhombic (S.G. Pbnm) symmet ry were found depending on the degree of substitution, x. Conductivity and Seebeck measurements show the presence of metal to insulator (M-I) transiti ons in these oxides and the different nature of the carriers. Magnetic susc eptibility measurements indicate important electronic delocalization that i s mainly controlled by composition. (C) 1999 Academic Press.