Effect of iron-doping on spin-state transition and ferromagnetism in Pr$_{0.5}$Ca$_{0.5}$CoO$_{3-δ}$ cobalt oxides

X. G. Luo; X. Li; G. Y. Wang; G. Wu; X. H. Chen

doi:10.1016/j.jssc.2006.04.011

paper

Effect of iron-doping on spin-state transition and ferromagnetism in Pr $_{0.5}$ Ca $_{0.5}$ CoO $_{3 - δ}$ cobalt oxides

arXiv:cond-mat/0509533 · doi:10.1016/j.jssc.2006.04.011

Abstract

Resistivity and dc magnetization measurements were performed for the polycrystalline Pr $_{0.5}$ Ca $_{0.5}$ Co $_{1 - x}$ Fe $_{x}$ O $_{3 - δ}$ ( $x$ = 0, 0.05, 0.10 and 0.15) samples. The as-fabricated samples exhibit ferromagnetic (FM) transition and the transition temperature increases with increasing the iron doping level. Annealing under high oxygen pressure induces a spin-state transition of Co ions in the \emph{iron-free} sample and such transition is reinforced with increasing the annealing oxygen pressure, while the annealing under high oxygen pressure suppresses the ferromagnetic ordering. Contrary to the case of the \emph{iron-free} sample, no spin-state transition is induced by the annealing under high oxygen pressure for the \emph{iron-doped} samples, and the ferromagnetic transition temperature is nearly independent of the annealing procedures. The enhancement of the spin-state transition in the \emph{iron-free} sample after annealing under high oxygen pressure should be attributed to the reduction of the cell volume. The suppression of the spin-state transition by the Fe doping is related to the enlargement of the cell volume and the stronger Fe-O bonds than Co-O bonds. The enhancement of the ferromagnetism by the iron-doping might arise from the ferromagnetic exchange interaction between Fe $^{3 +}$ and Co $^{4 +}$ through oxygen (Fe $^{3 +}$ -O-Co $^{4 +}$ ).

arXiv comment11 figures

Effect of iron-doping on spin-state transition and ferromagnetism in Pr0.5​Ca0.5​CoO3−δ​ cobalt oxides

Abstract

References in corpus (7)

Effect of iron-doping on spin-state transition and ferromagnetism in Pr $_{0.5}$ Ca $_{0.5}$ CoO $_{3 - δ}$ cobalt oxides