Fast and efficient synthesis of a new adjustable perovskite-structured ferrite La1−xCaxFeO3 microwave absorbent

Abstract

Rare-earth orthoferrites (RFeO3) is emerging as a type of microwave absorbing material (MAM) with development potential because of its excellent structural stability and moderate permittivity and amount of potential energy present. In this study, we employed a simple sol–gel technology to quickly synthesize La1−xCaxFeO3 (x = 0, 0.05, 0.1, 0.15, and 0.2) ferrite MAMs. The FullProf X-ray diffraction refinement demonstrated that all samples formed single-phase LaFeO3 (space group: Pnma). The amount of Ca doping was crucial in determining the particle size, magnetic properties, and electromagnetic parameters of LaFeO3. As a dielectric loss type in MAM, conduction loss is the primary reason and interfacial as well as dipolar polarizations are the secondary reasons for the attenuation of the electromagnetic energy of the samples. The study discovered that an appropriate amount of Ca2+ doping improves LaFeO3 microwave absorption. Therefore, the ideal microwave absorption is achieved in the La1−xCaxFeO3samples when Ca content x = 0.1 and 0.15, where the minimum reflection loss (RLmin) of La0.9Ca0.1FeO3 is − 39.90 dB at 6.72 GHz and the corresponding matching thickness is 4.0 mm. Although the RLmin of La0.85Ca0.15FeO3 is − 24.37 dB at 13.44 GHz, the effective absorption bandwidth is 4.56 GHz and the corresponding matching thickness is only 2.0 mm, which almost covers the entire Ku-band. This La1−xCaxFeO3 is expected to be an industrially produced high-performance MAM owing to its excellent microwave absorption performance as well as its simple and rapid synthesis method.