Engineering A-site cation deficiency into LaCoO thin sheets for improved microwave absorption performance

Rationally designing microwave absorption materials with highly efficient and tunable bandwidth is in great demand but remains a huge challenge. In this study, perovskite oxide LaCoO thin sheets have been obtained by the hydrothermal synthesis and subsequent annealing process. Then, cation deficiency is introduced to the A-site of LaCoO via a selectively etching strategy by FeCl solution. The phase characteristics, morphologies, structures, and microwave absorption performance of LaCoO thin sheets with A-site cation deficiency have been systematically investigated. The results indicate that a suitable introduction of the A-site cation deficiency is beneficial to induce more dipole polarization, leading to the enhancement of the microwave absorption performance. When the amount of FeCl is 0.3 g, the LaCoO thin sheets exhibited superior reflection loss characteristics in the range of test frequency. Exhilaratingly, a minimum reflection loss (RL) value of − 56.9 dB at 15.1 GHz can be achieved with a thin thickness of 2.0 mm. Meanwhile, a broad effective absorption bandwidth reaches 5.9 GHz, covering the range of 12.1–18.0 GHz. It is believed that introducing the A-site cation deficiency of LaCoO can be used as an effective means for tuning microwave absorption.