Structural and electromagnetic studies of Ni0.7Zn0.3Ho2xFe2-2xO4 ferrites

A series of holmium (Ho) doped nanocrystalline Ni0.7Zn0.3Ho2xFe2-2xO4; 0.0 <= x <= 0.07 ferrite was synthesized using the conventional ceramic technique. The cubic spinel structure was confirmed by powder X-ray diffraction (XRD). The lattice parameter increases with increase in Ho content due to large ionic radius of Ho3+ (0.901 A) as compared to Fe3+ (0.67 angstrom). Room temperature DC electrical resistivity and activation energy both increase with the increase of holmium contents. The saturation magnetization (M-s) decreased gradually from 78.92 to 54.17 emuig due to holmium ions substitution in Ni-Zn ferrites. This decrease in M-s is explained on the basis of redistribution of cations amongst the sites and weakening the A-B exchange interactions. An increase in electrical resistivity made this material suitable for its use in high frequency device applications. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.