Composition dependent magnetic and microwave properties of exchange-coupled hard/soft nanocomposite ferrite

In the present work, exchange-coupled BaFe12O19 (BaM)/Ni0.5Zn0.5Fe2O4 (NZFO) nanocomposites with different weight ratio were prepared by sol-gel autocombustion method. The effect of relative weight fraction on structural, morphological, magnetic and microwave properties were investigated. X-ray diffraction patterns of composites confirmed the co-existence of BaM and NZFO phases without any secondary phase. Smooth hysteresis loops without kink confirmed that BaM/NZFO phases were well exchange-coupled. Non linear change in magnetization (M-s) and coercivity (H-c) with NZFO content were observed. The drastic increase in M-s with corresponding sharp decrease in H-c for 70/30 wt ratio was observed. The change in M-s and H-c was explained with the schematic model of interfacial spin interactions. Complex permeability and permittivity in K-u-band showed oscillatory behaviour for higher weight fraction of NZFO. Reflection loss frequency found to depends on NZFO content and maximum loss (-41 dB) was observed for 70/30 wt ratio at 13.8 GHz frequency. (C) 2019 Elsevier B.V. All rights reserved.