M\"{o}ssbauer and magnetic studies of (Ni$_{0.6-x}$Co$_{x})$Zn$_{0.4}$Fe$_{2}$O$_{4 }$nanoparticles

Mixed-ferrites (Ni$_{0.6-x}$Co$_{x})$Zn$_{0.4}$Fe$_{2}$O$_{4}$ with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 were synthesized by co-precipitation of Ni-, Co-, Zn- and Fe-sulfates. Structural characterization of the approximately 10-nm particles was made by x-ray powder diffraction. Through M\"{o}ssbauer spectroscopic measurements, the composition- and temperature-dependence of magnetic blocking temperature and anisotropic constant were obtained. SQUID data yielded corroborative results, in addition to magnetization and saturation values.