Pseudo-binary composite of Sr2TiMoO6–Al2O3 as a novel microwave absorbing material

Abstract

In this work, a novel microwave absorbing material (MAM) made of a pseudo-binary of Sr₂TiMoO₆–Al₂O₃ (STM) is proposed first. The MAMs labeled as STM X (X = 60, 70, 80 and 100, respectively), in which X is the initial weight percent of Sr₂TiMoO₆, were synthesized using the solid-state reaction method. Compared with STM100, some equilibrium phases, including SrTiO₃, Mo, Sr₈(Al₁₂O₂₄)(MoO₄)₂ and a few undefined ones, are presented in the composites as evidenced by X-ray diffraction results and scanning electron microscopy due to the chemical reaction between Sr₂TiMoO₆ and Al₂O₃ component. Besides conductance loss, heterogeneous interfaces between various equilibrium phases introduce interfacial polarization, which causes an enhancement of dissipation for the incident electromagnetic wave. Among the synthesized samples, STM80 presents the best microwave absorbing properties. It has a minimum reflection loss (RL_min) of − 26 dB and an effective absorbing bandwidth up to 2.7 GHz when the thickness is only 1 mm. This indicates that STM80 is a new type of microwave absorbing material with strong absorption and ultrathin thickness.