Effect of the ionic radius of A-cations on the magnetic and magnetocaloric properties of charge-ordered manganite La0.5Ca0.5–x Sr x MnO3 (0 < x < 0.5)

Abstract

The effect of substitution of Sr2+ ions for Ca2+ ions on the magnetic and magnetocaloric properties of a charge-ordered La0.5Ca0.5MnO3 manganite has been studied. The direct and inverse magnetocaloric effects corresponding to the paramagnetic–ferromagnetic and ferromagnetic–antiferromagnetic transitions have been detected. It has been shown that the substitution Ca2+ → Sr2+ leads to the suppression of the charge-ordered phase and to an increase in the Curie temperature TC. The evolution of the destruction of the charge-ordered phase is nonmonotonic, which is associated with the change in the type of antiferromagnetic ordering.