Mossbauer study of Fe-57-doped La0.5Ca0.5MnO3

The first order antiferromagnet (AFM) to ferromagnet (FM) transition observ ed in La0.5Ca0.5MnO3 compound has been studied, both macroscopically and mi croscopically, by magnetization and Fe-57 Mossbauer measurements. The Mossb auer spectra reveal that Fe substitutes for Mn3+ as Fe3+ (S= 5/2). The zero -field-cooled and field-cooled Mossbauer spectra for the same field are com pletely different and can be fitted by predominantly AFM and FM components, respectively, in agreement with the magnetization data. In general, our da ta can be explained in the framework of a first-order, field-induced transi tion. [S0163-1829(99)09201-2].