Gallium substitution influence on microstructure and magnetic properties of Y-type Ba0.5Sr1.5Zn2Fe12O22 hexaferrites

Y-type hexagonal ferrites of Ba0.5Sr1.5Zn2Fe(12-x)GaxO22 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) are synthesized by chemical co-precipitation method. X-ray diffraction (XRD) analysis reveals that the samples are single-phase and the space group is R3m. The field-emission scanning electronic microscope (FE-SEM) results indicate that the grains are regular fibrous shape with a width of about 2-5 mu m and a thickness of 1-3 mu m. In the M-T diagram, it can be observed that the temperature at which the transition from helical to ferrimagnetic (TS) increases first and then decreases with increasing substitution amount x. From sigma-H, the values of coercive field (HC) experience alternating decreases and increases, and reaches a maximum value of 567.34 Oe at x = 0.8. While the specific saturation magnetization (sigma S) values exhibit a monotonic decrease with the increasing x. The variations in magnetic properties can tentatively be ascribed to the effect of Ga3+ substitution. These results above might be used as promising candidates in electric devices.