Structural and magnetic properties of Dy doped SrFe12O19 ferrites

Hexagonal Sr1_xDyxFe12O19 (x = 0.0-0.1) have been prepared by high-energy ball milling technique. The effect of Dy doping on the structural and magnetic properties is studied. Crystal structure, morphology and magnetic properties are investigated. Single polycrystalline phase of SrFe12O19 is obtained and proved by X-ray diffraction (XRD) analysis. All Sr1_xDyxFe12O19 samples displayed single polycrystalline phase whatever the amount of Dy is. Magnetic properties, as a function of magnetic field and of temperature, were examined before and after Dy doping. Significant improvement of saturation magnetization (Ms) and intrinsic coercivity (Hc) at room tem-perature were achieved as a result of the Dy substitution. High coercivity were observed for all samples, sug-gesting the materials are good candidates for high frequency applications. Remnant magnetization (Mr) is obtained from the hysteresis loop and found at 13.5 emu/g for the non-doped sample. The value showed sig-nificant increase, reaching 34.2 emu/g, with increasing the dopant (Dy) amount. Magnetic interactions were explored via temperature dependent zero field cooling (ZFC) and field cooling (FC) magnetization measure-ments. FC magnetization increased slowly with temperature reduction for the samples x = 0, 0.02 and 0.04, indicating the weakly coupled magnetic system. But for highly doped samples (x = 0.06 and 0.08) the FC magnetization decreased with decreasing of temperature, indicating the strong coupling interactions. The ZFC and FC magnetization data indicates that the blocking temperature (TB) is well above the room temperature.