Mössbauer spectra of CoZn-substituted Z-type barium ferrite Ba3Co2−xZnxFe24O41

Mössbauer spectra of powder and aligned Ba3Co2−xZnxFe24O41 samples with x=0–2.0 have been obtained and analyzed at room temperature and at T=7 K with applied magnetic fields of 0 and 60 kOe. The relationship between Mössbauer parameters and magnetic properties has been studied. The magnetocrystalline anisotropy of Ba3Co2−xZnxFe24O41 is modified from the c plane to the c axis at Zn concentration x=1.2–1.6, based on the dependence of the quadrupole splitting and hyperfine field on Zn substitution for powder samples, and the values of the angle factor b for aligned samples. Zn ions occupy only sites with down spin, while Co ions prefer sites with up spin. As the Zn substitution increases, the increase in saturation magnetization is attributed to the occupation of Zn ions at sites with down spin, which decreases the negative magnetization, thus increasing the net magnetization.