Electromagnetic and microwave absorption properties of carbonyl iron/La0.6Sr0.4MnO3 composites

In this work carbonyl iron/La0.6Sr0.4MnO3 composites were prepared to develop super-thin microwave absorbing materials. The complex permittivity, permeability and microwave absorption properties are investigated in the frequency range of 8–12 GHz. An optimal reflection loss of −12.4 dB is reached at 10.5 GHz with a matching thickness of 0.8 mm. The thickness of carbonyl iron/La0.6Sr0.4MnO3 absorber is thinner, compared with conventional carbonyl iron powders with the same absorption properties. The bandwidth with a reflection loss exceeding −7.4 dB is obtained in the whole measured frequency range with the thickness of 0.8 mm. The excellent microwave absorption properties are attributed to a better electromagnetic matching established by the combination of the enhanced dielectric loss and nearly invariable magnetic loss with the addition of La0.6Sr0.4MnO3 nanoparticles in the composites. Our work indicates that carbonyl iron/La0.6Sr0.4MnO3 composites may have an important application in wide-band and super-thin electromagnetic absorbers in the frequency range of 8−12 GHz.