Structural and magnetic properties of La~(3+) substituted strontium hexaferrite nanoparticles prepared by citrate precursor method

摘要

Lanthanum (La~(3+)) doped strontium ferrite is a promising material for high density perpendicular recording media due to high magnetocrystalline anisotropy and coercivity. The effects of La~(3+) on magnetic properties have been analyzed using vibrating sample magnetometer and discussed. The results show that the coercivity has been improved by substitution of La~(3+) on iron sites; coercivity value found to be increased with increase in La~(3+) content and is maximum for x=0.63 in SrLa_xFe_(12-x)O_(19), indicating the high magnetocrystalline anisotropy. La~(3+) doped strontium ferrite, prepared by citrate precursor technique, have been analyzed by means of X-ray diffraction (XRD), field emission scanning electron microscopy, fourier transform infrared spectroscopy and inductance capacitance resistance meter bridge. The XRD analysis shows that crystalline ferrite phase with hexagonal structure (P6_3/mmc) have been formed when the precursor calcined at 900℃ for 5 h. The crystallite size is found in the range of 31-38 nm and the elemental composition has been examined by energy dispersive X-ray. The dc electrical resistivity has been found to be increased with increasing La~(3+) content.