Optimizing the microwave absorption feature of LaCoO₃/Bi₂S₃ nanocomposite by regulating the filler loading content tested via waveguide and free-space methods

Electromagnetic absorbent materials have received significant attention, recently, due to the growing concern about microwave contamination caused by widespread electronic devices. So, a lot of work has been done to develop advanced absorbing materials with excellent performance. Here, Bi₂S₃ decorated LaCoO₃ nanocomposite has been fabricated via a solvothermal method. To study the microwave absorption properties, LaCoO₃@ Bi₂S₃ nanocomposites with 5, 15, 25, 35 and 40 wt% loadings were prepared. With optimal microwave absorption performance, a 35 wt% sample has decent minimum reflection loss (RL_mini) with qualified frequency bandwidth (RL > 10 dB) covering nearly the whole X-band. Enhancements in microwave absorption efficiency of 35 wt% sample are ascribed to the highest dielectric loss, highest magnetic loss, maximum attenuation constant, as well as optimal impedance matching value. Furthermore, the optimal sample is tested via two measurement techniques; waveguide and free-space methods. A Comparison has been drawn between the variation of reflection loss measured by both methods. The free-space approach proves a good alternative measurement technique with contact-free and non-destructive benefits. Our findings may be useful in the design and fabrication of LaCoO₃@ Bi₂S₃ nanocomposites for efficient microwave absorbers.