A Comparative Study of Structural, Magnetic and X-Band Microwave Absorption Characteristics of Pure and Zn, Zr Doped M-Type Barium Hexaferrites Samples

Abstract

Phase evolution in BaFe10ZnZrO19 (BZFO) and BaFe12O19 (BFO) samples calcined for six hours between 900 °C – 1200 °C has been studied using Rietveld refinement. The refinement data reveals that BZFO samples exhibit higher phase complexity comprising a maximum of five Zn-Zr doped BFO, ZnFe2O4, ZrO2, BaZrO3 and BaFeO3 phases at 1100 °C and 1200 °C. In contrast, BFO samples exhibit lesser phase complexity comprising only BFO and Fe2O3 phases. The FESEM micrographs reveal pronounced secondary grain growth in BZFO samples and reduction in grain size with dopant incorporation. The VSM data reveals that BFO samples exhibit superior magnetic characteristics as compared to BZFO samples. The BFO samples show minimum value -35.3 dB (at 8.8 GHz) and BZFO samples show minimum  value -36.6 dB (at 9.5 GHz) at 1200°C calcination. The data suggests an enhancement in microwave absorption capacity for both types of samples with increasing calcination temperature.

Keywords: Barium hexaferrite, Rietveld analysis, Solid state reaction technique, Surface morphology, Microwave characteristics, Magnetic properties