Hs. Yi et al., Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction, PHYS REV B, 61(1), 2000, pp. 428-431
From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped
manganites, including the antiferromagnetic superexchange interaction (J(A
F)) we found that the ferromagnetic ordering was suppressed as J(AF) increa
sed. The ferromagnetic transition temperature T-c, as obtained from a mean-
field fit to the calculated susceptibilities, was found to decrease monoton
ically with increasing J(AF). Further, the suppression in T-c scales with t
he bandwidth narrowing induced by the antiferromagnetic frustration origina
ting from J(AF) From these results, we propose that the change in the super
exchange 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 m
anganites of the type (La0.7-yPry)Ca0.3MnO3.