Nano-crystalline Magnesium Substituted Cadmium Ferrites as X-band Microwave Absorbers

Abstract The magnetic and electromagnetic properties of nanocrystalline spinel ferrites with chemical formula Mg x Cd 1−x Fe 2 O 4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) prepared by oxalate co-precipitation method under microwave sintering technique were studied. The magnetic and dielectric parameters of ferrites were determined by using vibrating sample magnetometer (VSM) and vector network analyzer (VNA) respectively. Magnetic parameters such as saturation magnetizations (M s ), coercive force (H c ), remnant magnetization (M r ), Yafet-Kittel (Y-K) angle of ferrites were determined from hysteresis loops. The variation of real permittivity (e′), dielectric loss tangent (tanδ e ), real permeability (µ′) and magnetic loss tangent (tanδ m ) with frequency and Mg 2+ content were studied in X-band frequency range. The values of e′, tanδ e , µ′ and tanδ m of ferrites were observed to be in range of 4.2 – 6.12, 2.9 × 10 −1 – 6 × 10 −2 , 0.6 – 1.12 and 4.5 × 10 −1 – 2 × 10 −3 respectively for the prepared compositions. The study of variation of reflection loss with frequency of all ferrites shows that ferrite with magnesium content x = 0.4 can be potential candidate for microwave applications in X-band.