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Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction

Hongsuk Yi·Jaejun Yu·Sung-Ik Lee
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Abstract

From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped manganites, including the antiferromagnetic superexchange interaction ($J_{AF}$), we found that the ferromagnetic ordering was suppressed as $J_{AF}$ increased. The ferromagnetic transition temperature $T_c$, as obtained from a mean field fit to the calculated susceptibilities, was found to decrease monotonically with increasing $J_{AF}$. Further, the suppression in $T_c$ scales with the bandwidth narrowing induced by the antiferromagnetic frustration originating from $J_{AF}$. From these results, we propose that the change in the superexchange interaction strength between the $t_{2g}$ electrons of the Mn ions is one of the mechanisms responsible for the suppression in $T_c$ observed in manganites of the type (La$_{0.7-y}$Pr$_{y}$)Ca$_{0.3}$MnO$_3$.

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Hongsuk Yi, Jaejun Yu, Sung-Ik Lee. 1999-10-11. Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction. https://doi.org/10.1103/physrevb.61.428

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