The Effect of Cation Distribution on Magnetic Properties of Zn۱-x Fe۱.۲ [(MnxNi۱-x)۰.۸ (CoxCu۱-x)۰.۲]x+۰.۸O۴ Ferrites and Determination of Optimal Magnetization

A series of NiCuMnCo-substituted zinc ferrites with the chemical formula of Zn۱-x Fe۱.۲ [(MnxNi۱-x)۰.۸ (CoxCu۱-x)۰.۲]x+۰.۸O۴ (where x=۰, ۰.۴ and ۰.۸) were prepared by the co-precipitation method. Using X-ray diffraction (XRD) analysis the single-phase cubic structure of samples was confirmed. The average crystallite size and lattice constant were obtained ۶-۹ nm and ۸.۳۸۶-۸.۳۹۹ Å, respectively. These parameters were increased with increasing x concentration. The field emission scanning electron microscopy revealed that the average particle sizes were in the range of ۱۱-۱۴ nm. From hysteresis loops of samples, the magnetization was determined in a magnetic field of ۸ kOe. The magnetization of un-calcined samples was not saturated. To reach saturation magnetization (Ms), all samples were calcined at ۹۰۰◦C. The results indicated the increase in Ms with the enhancement of x contents. This behavior was discussed via the core-shell model, Neel's theory, and the site's occupation of the substituted cations on the sub-lattices. The results showed the maximum and minimum magnetization on the calcined sample with x = ۰.۸ and the un-calcined sample with x = ۰.۰, respectively. The quality of particles was calculated using the squareness ratio. Also, the variations of coercivity (Hc) for all samples were investigated. With increasing x values, the Hc of calcined samples was decreased. It was discussed by the multi-domain structure of samples. The calcined sample with x=۰ showed maximum Hc. Generally, among all samples, the sample with x=۰.۸, due to maximum saturation magnetization and minimum Hc, can be suitable for high-frequency applications.

کلیدواژه ها:

NiCuMnCoZn ferrites ، Calcination ، Magnetic properties ، Core-shell ، Neel's theory