The temperature dependence of magnetic properties of Zn-Ti substituted Ba-ferrite particles for magnetic recording

It was shown that the morphological and magnetic properties of Zn-Ti doped Ba-ferrite particles are suitable for magnetic recording. In order to clari fy the temperature dependence of the magnetic properties of these particles , BaFe10.8-2xZnxTixO19 particles with the nominal composition x = 0.0-0.50 were prepared by synthesis from salt melts. The saturation magnetization M- s, magnetic anisotropy field H-A and magnetocrystalline anisotropy constant K-1 of the above-mentioned particle assemblies were estimated by using the law of approach to saturation of polycrystalline ferrite, and the Curie te mperature T-c was determined by the thermodynamic relation. With an increas ing x, the T-c decreased, while the lattice parameters a, c and M-s have an unnoticeable maximum at x = 0.20. The H-c(T) curves of samples with differ ent x show that all particles have positive temperature coefficient in the vicinity of room temperature, which decreases with increasing x. The M-s(T) , H-A(T) and K-1(T) were determined and discussed. (C) 1999 Elsevier Scienc e B.V. All rights reserved.