Investigation of magnetic and structural properties of Ni–Zr co-doped M-type Sr–La hexaferrites

In this research, Ni 2+ and Zr 4+ co-doped Sr–La hexaferrites Sr 0.7 La 0.3 Fe 12.0−2 x (NiZr) x O 19 (0.0 ≤ x ≤ 0.5) were synthesized by the standard ceramic method. The phase identification of the hexaferrites was confirmed by X-ray diffraction analysis. X-ray diffraction analysis showed that all the samples were in single phase M-type hexagonal structure and no impurity phase was observed. Lattice parameters ( c and a ) increased with increasing NiZr content ( x ) from 0.0 to 0.5. The morphology of the hexaferrites was analyzed by a field emission scanning electron microscopy (FE-SEM). FE-SEM micrographs showed that the grains exhibited hexagonal shape in a plate-like structure with clear grain boundaries. Magnetization properties of the hexaferrites were carried out at room temperature using a physical property measurement system-vibrating sample magnetometer. The values of saturation magnetization ( M s ), remanent magnetization ( M r ) and coercivity ( H c ) were calculated from magnetic hysteresis ( M – H ) loops. M s and H c decreased with increasing NiZr content ( x ) from 0.0 to 0.5. M r and M r / M s ratio first increased with increasing NiZr content ( x ) from 0.0 to 0.1, and then decreased when NiZr content ( x ) ≥ 0.1.