Mossbauer and X-ray studies for Ni0.2ZnxMg0.8-xFe2O4 ferrites

The spinel ferrites of Ni0.2ZnxMg0.8-xFe2O4, 0 less than or equal to x grea ter than or equal to 0.8, were studied at room temperature using X-ray diff raction and Mossbauer patterns. The analysis of the X-ray diffraction patte rns proved that the samples have a single phase cubic spinel structure. The calculated values of the theoretical, true and average lattice constants, tetrahedral bond, tetrahedral edge and unshared octahedral edge were found to increase while the shared octahedral edge and octahedral bond decrease a s the Zn2+ ion substitution increases. Mossbauer studies showed that the sa mples for x = 0, 0.2 and 0.4 are magnetic and show rather broad lines, whil e for x = 0.6 and 0.8 are paramagnetic. The hyperfine parameters of the tet rahedral and octahedral sites were determined as functions of composition v . The cation distributions were deduced and supported by X-ray studies. The B-site pattern was composite and has been fitted into multicomponents and the deduced hyperfine parameters have been discussed as a function of x. (C ) 2001 Elsevier Science B.V. All rights reserved.