Preparation and magnetic properties of (Zn-Sn) substituted barium hexaferrite nanoparticles for magnetic recording

Zn-Sn substituted barium ferrite particles BaFe(12-2x)Zn(x)Sn(x)O(19) with 0 less than or equal to x less than or equal to 1.1 have been prepared by a chemical co-precipitation method for the first time. X-ray diffraction (XRD) and transition electron microscopy (TEM) have been carried out to determine the particle structure and morphology. Magnetic properties have been measured using a vibrating sample magnetometer (VSM) with an applied field up to 80 kOe. The specific saturation magnetization M(s) was determined using the law of approach to saturation, and the effective anisotropy field H(a) and anisotropy constant K(1), were also estimated. It was found that the particle size could be effectively decreased and coercivity H(c) easily controlled, by varying x without significantly decreasing saturation magnetization. In particular, BaFe(12-2x)Zn(x)Sn(x)O(19) with x = 0.7-1.1 has suitable magnetic characteristics and a particle size small enough for high-density magnetic recording. (C) 1998 Elsevier Science B.V. All rights reserved.