Influence of Nd-NbZn co-substitution on structural, spectral and magnetic properties of M-type calcium-strontium hexaferrites Ca0.4Sr0.6-xNdxFe12.0-x(Nb0.5Zn0.5)xO19

This is first report on Nd-NbZn co-substituted M-type Ca-Sr hexaferrites with nominal compositions Ca0.4Sr0.6-xNdxFe12.0-x(Nb0.5Zn0.5)xO19 (x = 0.00-0.32) fabricated by the conventional solid-state reaction method. X-ray diffractometer (XRD), Fourier transformer infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), physical property measurement system-vibrating sample magnetometer (PPMS-VSM) were employed to characterize M-type calcium-strontium hexaferrites. XRD patterns of the hexaferrites with Nd-NbZn content (x) of 0.00 ≤ x ≤ 0.16 showed the single M-type hexaferrite phase. However, for the hexaferrites with Nd-NbZn content (x) ≥ 0.24, the impurity phase (α-Fe2O3) was observed. FT-IR frequency bands in the range (592-613) cm−1 and (430-470) cm−1 corresponded to the formation of tetrahedral and octahedral clusters of metal oxides in the hexaferrites, respectively. FE-SEM micrographs showed that the grains were platelet-like shapes. The saturation magnetization (Ms) and magneton number (nB) decreased with increasing Nd-NbZn content (x) from 0.00 to 0.32. The remanent magnetization (Mr) first increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08. The Mr/Ms ratio, coercivity (Hc) and magnetic anisotropy field (Ha) increased with increasing Nd-NbZn content (x) from 0.00 to 0.32. First anisotropy constant (K1) first slightly increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08.