Magnetic studies of Sn 0.2 Cr 1.8−x Fe x O 3 compounds prepared via the hydrothermal route

Abstract Tin–iron chromium oxides (Sn 0.2 Cr 1.8− x Fe x O 3 with x varying from 0.3 to 1.3) have been produced by hydrothermal process in a stirred pressure reactor from pure metal chlorides. Single phase corundum structure and nanophase structure of the as-synthesized samples were confirmed by X-ray diffraction (XRD) and by transmission electron microscope (TEM). The results show that the produced powders have grain sizes in the range 25–34 nm. 57 Fe Mossbauer spectra show the materials to be paramagnetic for Fe concentration x ≤0.5 and in ordered magnetic state at higher concentration. The variations of grain sizes, lattice parameters, and Mossbauer parameters as a function of composition have also been investigated. The coercivity increases rapidly with size, attaining a maximum value, and then decreases with size of the particles.