Magnetic and Mössbauer studies on nanocrystalline Co1−x Li x Fe2O4 (x = 0, 0.2)
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Ultrafine particles of Co1 − x Li x Fe2O4 (x = 0, 0.2) samples are prepared by glycine–nitrate combustion route. X-ray diffraction and transmission electron microscopy studies show that the samples have cubic spinel structure and average crystallite sizes of x = 0 and 0.2 are 36 and 44 nm respectively. Vibrating sample magnetometer studies revealed the ferromagnetic nature of the samples. Li-doped CoFe2O4 sample showed higher values of coercive field, remanent magnetization and saturation magnetization compared to pure CoF2O4 indicating the enhancement of magnetic interactions. Mössbauer spectra at 77 K exhibited two broad sextets indicating that Fe3 + ions occupy both tetrahedral and octahedral sites. From these studies, it is concluded that Co1 − x Li x Fe2O4 (x = 0, 0.2) samples exhibit an inverse spinel structure. At room temperature, two sextets are superimposed on a very broad non-Lorentzian background indicating the presence of superparamgnetic fraction in agreement with the microscopic observations.
KeywordsMössbauer studies Ferrites CoFe2O4 sample
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