Pressure effects on the magnetic transition temperature in ordered double perovskites

Abstract

A study of the pressure effect on the Curie temperature in polycrystalline ordered double perovskites was carried out by measuring the temperature dependence of the magnetization in isoelectronic Sr₂FeMoO₆, Ba₂FeMoO₆, and Ca₂FeMoO₆, and in W-substituted Sr₂FeMo_1−xW_xO₆ with x=0.70. Pressure up to approximately 10 kbar induces an increase in the Curie temperature in all the samples with different rate: dT_c/dp results to be 1.7(2) K/kbar for Ba₂FeMoO₆, 0.60(8) K/kbar for Sr₂FeMoO₆, 0.25(8) K/kbar for Ca₂FeMoO₆, and 0.7(1) K/kbar for the W-substituted sample. The results are interpreted in terms of the different lattice structure and cell volume of the investigated systems. A manganitelike model was only partially successful in explaining the observed pressure behavior, thus, pointing out the different nature of the magnetic interaction in doped manganites and in ordered double perovskites.