SYNTHESIS, MAGNETISM, AND ELECTRICAL-PROPERTIES OF LA1-XBAXTIO3 (0.0 LESS-THAN-OR-EQUAL-TO X LESS-THAN-OR-EQUAL-TO 0.5)

The study of cation substitution in transition-metal oxides provides fundamental information needed to understand such phenomena as high-T(c) superconductivity and magnetic order in oxide materials. The solid solution La1-xBaxTiO3 (0.0 less-than-or-equal-to X less-than-or-equal-to 0.5) has been prepared by arc melting stoichiometric amounts of LaTiO3 and BaTiO3 under argon. Single-phase samples can be made for the stoichiometry range studied here. The polycrystalline samples have been characterized using electron microprobe, thermal gravimetric analysis, temperature- and field-dependent magnetization, and dc resistivity. The stoichiometries determined by microprobe agree well with the theoretical stoichiometries. LaTiO3 is a canted antiferromagnet which shows a net ferromagnetic ordering at 150 K. The ferromagnetic order is destroyed with the addition of 5 % BaTiO3. All of the La1-xBaxTiO3 (x > 0) samples exhibit temperature-independent magnetism in the high-temperature (160-300 K) range and paramagnetism in the low temperature (< 50 K) region. The La1-xBaxTiO3 samples display poor metallic conductivity. In addition, several random samples display a sharp drop in resistivity which is reminiscent of PTCR thermistor behavior.