Development of doped Ba–Sr hexagonal ferrites for microwave absorber applications: Structural characterization, tunable thickness, absorption peaks and electromagnetic parameters

In this work, we report microwave absorption characteristics of Ba0·5Sr0·5(CoCr)xFe(12-2x)O19 hexaferrite prepared by a two route ceramic technique. The effect of Co2+-Cr3+content on structural, complex permittivity/permeability and reflection loss properties in Ba0·5Sr0·5Fe12O19 ferrite has been studied. X-ray diffraction confirmed the magnetoplumbite phase in the compositions. The dual absorption peaks were revealed in x = 0.8 composition with reflection loss of −52.09 dB at 8.78 GHz and 5.6 mm thickness. The absorption peaks were found to shift to low frequency with an increase in thickness. Composition x = 0.6 displayed the bandwidth to thickness ratio of 6.5 and a percentage bandwidth of 32.37% at 1.7 mm thickness and 10.13 GHz. The doping of Co2+ and Cr3+ reduced thickness, increased absorption, and bandwidth which is attributed to electromagnetic parameters, input impedance, quarter wavelength theory, and eddy current loss. The investigated performance parameters of prepared compositions indicate good scope for absorber applications. •Microwave absorption characteristics of M-type Co–Cr doped Ba0·5Sr0·5Fe12O19 hexaferrites has been investigated from 8.2 to 12.4 GHz.•The doping decreased the thickness for −10 dB absorption in the compositions.•The dual absorption peaks were observed in x = 0.8 composition with reflection loss of −52.09 dB at 8.78 GHz and 5.6 mm thickness.•The height of RL peaks can be tuned by doping, frequency, and thickness of compositions.•Composition x = 0.6 displayed the bandwidth to thickness ratio of 6.5 and a percentage bandwidth of 32.37% at 1.7 mm thickness and 10.13 GHz, implying good scope for absorber applications.