Coupling NiCo₂S₄ micro-spheres surface with worm-like AgBr nanoparticles: An effective strategy to cover X-band frequency range with thin thickness

In this study, achieving NiCo₂S₄/AgBr composites is a step in the right direction toward developing efficient microwave absorption fillers. The rough-surfaced NiCo₂S₄/AgBr coupled micro-sphere offers a significant enhancement in complex permittivity by changing filler loadings, due to the Debye relaxation process and high conductivity. Moreover, as an efficient wave absorber, the optimal sample demonstrates a decent minimum reflection loss (RL_mini) value of −17 dB and its qualifying absorption bandwidth (with RL < −10 dB) astonishingly encompasses the entire X-band (4 GHz). Additionally, the free-space technique was used to analyze the best sample, and the outcomes were compared. Touch-free and non-invasive nature of the free-space methodology has shown it to be a potentially viable testing method. So, comprehensive structural and compositional characterization, along with tunable properties and alternative testing method for preparing superior-quality NiCo₂S₄/AgBr samples, paves the way for exciting new microwave absorbents. Hence, NiCo₂S₄/AgBr is anticipated to be a very effective microwave absorber.