Microstructure characterization and magnetic behavior of NiAlxFe2−xO4 and Ni1−yMnyAl0.2Fe1.8O4 ferrites

NiAlxFe2−xO4 and Ni1−yMnyAl0.2Fe1.8O4 ferrites were prepared by the conventional ceramic method and were characterized by X-ray diffraction, scanning electron microscopy, and magnetic measurements. The single spinel phase was confirmed for all prepared samples. A proper explanation of data is possible if the Al3+ ions are assumed to replace Fe3+ ions in the A and B sites simultaneously for NiAlxFe2−xO4 ferrites, and if the Mn2+ ions are assumed to replace Ni2+ ions in the B sites for Ni1−yMnyAl0.2Fe1.8O4 ferrites. Microstructural factors play an important role in the magnetic behavior of Ni1−yMnyAl0.2Fe1.8O4 ferrites with large Mn2+ content.