Microstructure and magnetic properties of Zr-Mn substituted M-type SrLa hexaferrites

In this study, we have synthesized the M-type SrLa hexaferrites with nominal compositions of Sr0.75-La0.25Fe12.0-2x(ZrMn)(x)O-19 (0.0 <= x <= 0.75) by the solid-state method techniques. The phase compositions of the samples were confirmed by X-ray diffraction analysis. X-ray diffraction analysis exhibits that all the synthesized M-type hexaferrite magnetic powders are in single magetoplumbite structure and no impurity phase is observed, and with the increase of ZrMn content (x), (107) and (114) peaks are broadened and the 2 theta values of (107) and (114) peaks shift towards lower angles. It is observed that lattice constants (c and a) increase with increasing ZrMn content (x) from 0.00 to 0.75. The morphology of the M-type hexaferrites was characterized by a field emission scanning electron microscopy (FE-SEM). FE-SEM images show that the M-type hexaferrite have formed hexagonal structures. Magnetization properties were measured at room temperature using a physical property measurement system-vibrating sample magnetometer. The saturation magnetization (M-s), remanent magnetization (M-r) and coercivity (H-c) are calculated from magnetic hysteresis loops. M-s, M-r and M-r/M-s ratio first increase with increasing ZrMn content (x) from 0.00 to 0.15, and then decrease when ZrMn content (x) >= 0.15. H-c decreases with the increase of ZrMn content (x) from 0.00 to 0.75.