Influence of Mg Content on Structural and Magnetic Properties of Green-Synthesized Li0.5–0.5xMgxFe2.5–0.5xO4 (0.0 ≤ x ≤ 0.8) Nanoferrites

Abstract

Honey green synthesis of Li0.5–0.5xMgxFe2.5–0.5xO4 (x = 0.0, 0.1, 0.4, 0.6, 0.8) ferrites, thermally annealed at 450 °C for 3 hours, is reported. Structural, magnetic properties were investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). An antistructural modeling was used for describing active surface centers in the studied samples. XRD validates the formation of nanocrystalline spinel phase with Scherrer’s grain diameter varying between 23.4 and 26.3 nm. The present study implies that Mg2+ addition: (i) Modifies experimental lattice parameter (aexp), showing incorporation of Mg2+ ion in the spinel lattice (ii) Leads to cationic redistribution, showing the presence of Fe3+, Li1+, and Mg2+ ions on A and B sites (iii) Changes inversion parameter “δ” range between 0.65 and 0.75, demonstrating the mixed spinel character (iv) Alters saturation magnetization (Ms (exp)), understood in terms of cationic redistribution at A and B sites (v) Alters coercivity “Hc” (range between 90.3 Oe and 126.7 Oe) and shows more softer magnetic behavior for higher Mg content (vi) Affects Hc, and its variation with grain diameter D suggests that the studied samples fall in the overlap between single-domain or multi-domain structures (vii) Shows discrepancy between the experimental and calculated Ms values, suggesting that the magnetic arrangement of spins in the studied samples is not governed by a perfectly collinear antiparallel alignment, as proposed by Néel’s model, but rather affected by a spin canting (evidenced by finite canting angle “αy-k”) in the studied samples which can be explained by the three-lattice model suggested by Yafet and Kittel.