Microwave absorbing properties of La0.7Sr0.3MnO3 composites with negative magnetic susceptibility

Abstract

The complex permittivity and permeability of La0.7Sr0.3MnO3 (LSMO)-epoxy composite absorbers are investigated in the microwave ranges from 2 to 18 GHz by transmission/reflection method. A negative magnetic susceptibility of perovskite oxides has been obtained in the frequency range of 4–18 GHz. By the use of the cavity perturbation technique, the negative magnetic susceptibility for 7.5–14 GHz is reconfirmed. For LSMO-epoxy composite with 80 wt % fillers, the maximum reflection loss can reach 23 dB at 10.5 GHz and the absorbing bandwidth above 10 dB is 1.5 GHz with 2 mm thickness.