PHASE TRANSFORMATIONS OF YBaCuFeO_5 AT 460 AND 560 K

摘要

The thermal expansion, electrical conductivity ,dielectric permittivity, and dielectric loss tangent of YBaCuFeO_5 were measured in air in the temperature range 293-1120 K.YBaCuFeO_5 was found to undergo two phase transformations at 460 and 560 K, the former associated with antiferromagnetic ordering, and the latter involving a transition from semiconducting behavior to metallic conductivity. The apparent activation energy of conductivity in YBaCuFeO_5 was determined to be 21.2±0.9 kJ/mol at temperatures below 560 K.The average thermal expansion coefficient was evaluated for different temperature ranges.