Magnetic properties of Cd and Al substituted cobalt ferrite

464-468<span style="font-size: 16.0pt;mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman","serif""="">The crystal structure and magnetic properties of simultaneously substituted cadmium and aluminium spinel series Co1-xCdxFe2-xAlxO4 with x=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, are studied by X-ray diffraction and saturation magnetization measurements. The single phase fcc spinel structure of all the samples was confirmed by X-ray diffraction. X-ray analysis showed that the latticc parameter <span style="font-size:14.5pt; mso-bidi-font-size:7.5pt;font-family:" arial","sans-serif""="">'a', increases with increasing x. The apparent density and X-ray density exhibit similar behaviour. The Bragg peaks of XRD patterns were used to determine the possible cation distribution among the tetrahedral (A) and octahedral rB] sites. X-ray intensity calculations indicate that Cd<span style="font-size:13.5pt; mso-bidi-font-size:6.5pt;font-family:" times="" new="" roman","serif""="">2+ and Al<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt; font-family:" times="" new="" roman","serif""="">3+ ions occupy tetrahedral (A) and octahedral [B] sites respectively, while Fe3+ ions occupy both tetrahedral (A) and octahedral [B] sites. <span style="font-size: 16.0pt;mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman","serif""="">&nbsp; The saturation magnetization ‘σs’<span style="font-size:16.0pt; mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman","serif""="">and magneton number 'nB' (the saturation magnetization per formula unit) measured at 300 K using high field hysteresis loop technique decrease with increasing x, suggesting decrease in ferrimagneric behaviour. Neel's two sublattice model is applicable up to x≤ 0.2 while Y-K three sublattice model is applicable for x≥ 0.2. The cation distribution obtained from magnetization data is in good agreement with the cation distribution estimated from X-ray intensity calculations. The Neel temperature <span style="font-size:15.5pt; mso-bidi-font-size:8.5pt;font-family:" arial","sans-serif""="">TN deduced from a.c. susceptibility data decreases with x, suggesting a decrease in ferrimagnetic behaviour.<span style="font-size:25.0pt;mso-bidi-font-size: 11.0pt">