Structural and magnetic properties of Co$_{1+y}$Sn$_y$Fe$_{2�??2y�?�x}$Cr$_x$O4 ferrite system

[摘要] The samples of the series Co$_{1+y}$Sn$_y$Fe$_{2â€�??2yâ€�?�x}$Cr$_x$O₄ ferrites with ð‘�? = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and ð‘�? = 0.05, were prepared by the usual double sintering ceramic technique. The single-phase spinel structure of the samples was confirmed by using X-ray diffractometry technique. The lattice parameter `𝑎â€�? with an accuracy of ± 0.002 Ã�? were determined using Bragg peaks of XRD pattern. The lattice parameter `𝑎â€�? decreases with concentration, ð‘�?, which is due to the difference in the ionic radii of Cr³⁺ and Fe³⁺ ions. The X-ray intensity calculations were carried out in order to determine the possible cation distribution amongst tetrahedral (A) and octahedral [B] sites. The X-ray intensity calculations show Cr³⁺ ions occupying B site. The saturation magnetization, $sigma_{s}$, and magneton number, $n_B$ (the saturation magnetization per formula unit), measured at 300 K determined from high field hysteresis loop technique decrease with increase in concentration, ð‘�?, suggesting a decrease in ferrimagnetic behaviour. Thermal variation of low field a.c. susceptibility measurements from room temperature to about 800 K exhibits almost normal ferrimagnetic behaviour and the Curie temperature, $T_C$ determined from a.c. susceptibility data decreases with increase in ð‘�?.

[学科分类] 材料工程

[关键词] Spinel ferrite;cation distribution;magnetization;a.c. susceptibility;Curie temperature.