Magnetic and microwave absorption properties in 2.6–18 GHz of A-site or B-site substituted BaFe12O19 ceramics

Abstract

The A-site substituted (20 mol% Sr2+ and Ca2+) and B-site substituted (20 mol% Co3+ and Mn3+) M-type BaFe12O19 (BFO) ceramics were synthesized and the magnetic properties and microwave absorption were investigated. The A-site substitution by Ca2+ or B-site substitution by Co3+ can effectively modify the magnetic properties of the M-type BFO. The B-site dopant suppresses the complex permittivity more greatly than A-site ones and substitution of Co3+ at B-site changes the microwave permeability response to a resonate-like manner in 2.6–18 GHz. The A-site substitution is more effective on the enhancement of peak absorption whilst B-site substitution is more effective on the enhancement of absorption bandwidth. A wide bandwidth of reflection loss (RL) value below − 5 dB (> 70% microwave absorption) of the BaFe11.8Mn0.2O19 ceramic is obtained in 3.6–18 GHz and the minimum RL of − 18.5 dB is obtained at 7.2 GHz with a thickness of 2.5 mm.