Accepted Paper

Magnetisation and Curie Temperature Studies on Some Li-Cd Ferrites

S.N. Kulkarni1, P.D. Patil1, J. Nagaral1, B.K. Chougule2
1Doodhsakhar Mahavidyalaya, Bidri, Taluka Kagal, District Kolhapur, Maharashtra, India-416208
2Shivaji University, Kolhapur, Maharashtra, India
Abstract. Hysteresis loops for Li-Cd ferrites with the general formula Li0.5-x/2Fe2.5-x/2CdxO4 (with x = 0, 0.1, 0.2, ..., 0.7$) exhibits good rectangular properties. For the low concentration of Cd,sup>2+, the squareness of the hysteresis loop is preserved. For the higher concentration of Cd2+, hysteresis loop rectangularity is impaired. The magnetic moment for Li-ferrite is 2.19 μB and increases with increase in Cd content up to x = 0.2 and then decreases. The measured value of magnetisation of Li-ferrite at 300 K is 2806 gauss. The maximum value of magnetisation about 3640 gauss has been obtained for Cd2+ concentration of 20% and then decreases with increase in Cd content. The observed variation in magnetisation is due to changes in the number of tetrahedral and octahedral coordinated Fe3+ ions which are coupled ferrimagnetically via a super exchange interaction. The initial increase of magnetisation up to x = 0.2 is explained on the basis of Neel's two sublattice model. For the samples x > 0.2 Y-K angle increases as Cd increases and magnetisation decreases. The Curie temperature (Tc) of the samples in the series were obtained by Loroia technique and it is found that with increase in Cd2+ content the Curie temperature decreases. The overall strength of the A-B interaction determines the Curie temperature of the compound. A decrease in the super exchange interaction decreases the Curie temperature.

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