Synthesis of non-collinear (spin canted) ferrites having the formula, CoCd𝑥Fe2−𝑥O4 (𝑥 = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), has been carried out using the sol–gel auto combustion method. The ferrite samples show an interesting magnetic transition from Neel to Yafet–Kittel configuration, as the Cd2+ concentration is increased beyond 𝑥 = 0.4. The FT–IR spectra confirm the formation of the metal oxide bond as they exhibit two frequency bands in the range of ∼595 cm-1 and ∼450 cm-1, corresponding to the tetrahedral and the octahedral stretching vibrations of the metal oxide, respectively. The structural evolutions of the nanophase investigated using powder X-ray diffraction (XRD) technique show that the average crystallite size is ∼35 nm. The magnetic studies reveal that the saturation magnetization, 𝑀s, increases up to 𝑥 = 0.4 and decreases when the value of 𝑥 is > 0.4. It is proposed that the incorporation of Cd2+ ion takes place into the tetrahedral sites and up to 𝑥 = 0.4, Neel’s model is followed. But for 𝑥 > 0.4, canting of spins occurs, as explained by Yafet–Kittel (Y–K) model. The d.c. resistivity decreases as a function of temperature, indicating semiconducting nature of the ferrites and the positive value of Seebeck coefficient establishes 𝑝-type conduction behaviour for all the ferrite samples.
Volume 43, 2020
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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