Metal-to-insulator transition in La1-xBaxTiO3 - art. no. 045113

The ferroelectric insulator BaTiO3 can be electron-doped by substitution of divalent Ba2+, with trivalent La3+, creating d states at the transition-me tal sites. The successive filling of the 3d Ti band initiates a sequence of electronic transitions. First, the system undergoes an Anderson-type insul ator-to-metal-transition into a paramagnetic and metallic state, and second , a correlation-induced antiferromagnetic and insulating phase is establish ed for La-rich concentrations. Ceramic La1-xBaxTiO3 samples covering the wh ole concentration range were systematically examined utilizing measurements of resistivity, specific heat, and magnetic susceptibility in the temperat ure range 1.8< T< 300 K. The concentration dependence of the Sommerfeld coe fficient gamma and the Pauli spin susceptibility was systematically investi gated. The temperature dependence of the resistivity was studied in detail. In addition a (T,x) phase diagram of La1-xBaTiO3 was constructed.