Impact of Nd 3+ Substitutions on the Structure and Magnetic Properties of Nanostructured SrFe 12 O 19 Hexaferrite.

In this study, SrFe 12-x Nd x O 19 , where x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5, was prepared using high-energy ball milling. The prepared samples were characterized by X-ray diffraction (XRD). Using the XRD results, a comparative analysis of crystallite sizes of the prepared powders was carried out by different methods (models) such as the Scherrer, Williamson-Hall (W-H), Halder-Wagner (H-W), and size-strain plot (SSP) method. All the studied methods prove that the average nanocrystallite size of the prepared samples increases by increasing the Nd concentration. The H-W and SSP methods are more accurate than the Scherer or W-H methods, suggesting that these methods are more suitable for analyzing the XRD spectra obtained in this study. The specific saturation magnetization ( σ s ), the effective anisotropy constant ( K eff ), the field of magnetocrystalline anisotropy ( H a ), and the field of shape anisotropy ( H d ) for SrFe 12-x Nd x O 19 (0 ≤ x ≤ 0.5) powders were calculated. The coercivity ( H c ) increases (about 9% at x = 0.4) with an increasing degree of substitution of Fe 3+ by Nd 3+, which is one of the main parameters for manufacturing permanent magnets.