MAGNETIC-PROPERTIES OF SOME TETRAVALENT RARE-EARTH PEROVSKITES

The temperature dependence of the magnetic susceptibility for 1.5 < T < 300 K, the field dependence of the magnetization M (H), for O < H < 23 T and 1.5 < T < 15 K, and the temperature dependence of the heat capacity C(T), for 5 < T < 95 K are reported for the insulating distorted-perovskite systems PrBaO3, TbBaO3, TbSrO3, and CeBaO3, and the pseudoternary system (Pr,Ce)BaO3. X-ray analysis at room temperature indicates single-phase structures for all materials. PrBaO3 shows magnetic ordering below T(N) = 11.7 K, possibly due to a canted antiferromagnetic structure. T(N) is nearly independent of applied field up to about 12 T. High-field M(H) isotherms show a well-defined upward sloping kink at 12.7 T, which is independent of temperature for T < 9.5 K. This is indicative of a spin-reorientation transition. The pressure dependence of T(N) is negligible: dT(N)/dP < 0.1 K/kbar. TbBaO3 and TbSrO3 both show antiferromagnetic ordering, but with low-field hysteresis effects below 34 K. Clear C(T) anomalies at T(N) = 11.7 and 34 K are seen for PrBaO3 and TbBaO3, respectively. CeBaO3 is paramagnetic, but shows no magnetic order down to 1.8 K, although M(H) is field dependent at 4.2 K. The results in the Pr-based system are compared with previous work in high-T(c)-related Pr-based systems.