Quantifying heterogeneous interface effect of Fe3O4(111)/C for enhanced low-frequency electromagnetic wave absorption

How to tailor electromagnetic parameters of multi-component materials is the fundamental issues for low-frequency electromagnetic wave absorbers (EMA). However, there remains a challenge to accurately elucidate the impact of respective components at heterogeneous interfaces on the EMAs, not to mentioning the further quantitative contribution of the interfacial effect to the electromagnetic loss. In this paper, we for the first time separated the Fe₃O₄(111)/C heterogeneous interface of Fe₃O₄@C via a controllable interfacial separation strategy, meanwhile ensuring the consistent microstructure and the ratio of each component, as well as the unchanged macroscopic structure of the particles. Once all potential influences on electromagnetic parameters have been independently studied, the unique difference in heterogeneous interfaces enabled us to quantitatively evaluate the effect of them on electromagnetic parameters. Both experimental and density functional theory (DFT) calculation results consistently demonstrate that the Fe₃O₄(111)/C heterointerface increases carrier concentration and conductivity, thereby enhancing the imaginary part of the dielectric constant. Very distinguished from traditional interfacial polarisation mechanism presented in previous publications, this study introduces a novel interfacial loss mechanism primarily characterized by conductivity loss, which is rigorously investigated in a quantitative way. This discovery offers a novel approach for designing controllable heterogeneous interfaces and manipulating electromagnetic parameters in multicomponent EMAs.