Magnetic structural characterization of Mg-Co-Cr ferrite by neutron diffraction

Yunus, S. M.*; Yamauchi, Hiroki   ; Zakaria, A. K. M.*; Igawa, Naoki   ; Hoshikawa, Akinori; Ishii, Yoshinobu

Temperature dependent neutron diffraction studies were done on the spinel oxide system MgCoCrFeO (, 0.25, 0.50, 0.75 and 1.0). Neutron diffraction data recorded in the temperature range 10,,810 K were analyzed in the Rietveld method. Ordered sublattice magnetic moments of the five compositions of the spinel series at various temperatures were deduced from the analysis. A decreasing ordered moment with increasing substitution () was found indicating a gradual weakening of ferrimagnetic order. Huge diffuse signals around the 1,1,1 Bragg diffraction peak were found in the neutron patterns of the composition ,=,1.0 below the Curie temperature manifesting a build-up of short-range magnetic spin clusters. The observed features suggest a canted ferrimagnetic structure in the composition range ,,0.75 and a semi-spin glass like transition at ,=,1.0.