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-metal sites. The successive filling of the 3d Ti band initiates a sequence of electronic transitions. First, the system undergoes an Anderson-type insulator-to-metal-transition into a paramagnetic and metallic state, and second, a correlation-induced antiferromagnetic and insulating phase is established for La-rich concentrations. Ceramic La1-xBaxTiO3 samples covering the whole concentration range were systematically examined utilizing measurements of resistivity, specific heat, and magnetic susceptibility in the temperature range 1.8< T< 300 K. The concentration dependence of the Sommerfeld coefficient gamma and the Pauli spin susceptibility was systematically investigated. The temperature dependence of the resistivity was studied in detail. In addition a (T,x) phase diagram of La1-xBaTiO3 was constructed.