Magnetic properties of newly synthesized rare-earth contained M-type ferrites

The appeared phases and magnetic properties of ferrites of the RE2O3-AM2O-Fe2O3 system (RE=Y,La,Ce,Pr,Nd,Sm,Gd, and AM=Na,K,Rb) were studied. The observed phases were classified according to the combination of rare-earth metal and alkaline metal. M-type ferrites were obtained in the La2O3-AM2O-Fe2O3 system (AM=Na,K,Rb). The almost single phase of La-AM ferrites with magnetoplumbite structure was prepared in nominal composition of (La0.5Na0.5)O.4Fe2O3 and (La0.7K0.3)O.5Fe2O3. The crystal structure and magnetic properties of these ferrites were studied. The Rietveld profile analysis of XRD data indicates that the structural parameters of these ferrites are refined to weighted pattern Rwp factor of about 6%. The magnetization of these ferrites is about 70-80 μWbmkg-1 at room temperature at the applied field of 1200 kAm-1, and their Curie temperature is about 710K-730K. The anisotropy field is about 1100 kAm-1. The Zn2+ stabilized La-M type ferrites are also synthesized. It was found that the LaZn0.5Fe11.5O19 has the saturation magnetization of around 81.4 μWbmkg-1 at the applying field of 1200 kAm-1 and the Curie temperature of 649 K. (orig.)