Effects of Particle Size on Electromagnetic and Microwave Absorption Properties of La0.7Sr0.3MnO3±δ-Epoxy Composite

La0.7Sr0.3MnO3±δ powders were fabricated by solid-state reaction method at 1473 K for 4 h. The precursors were prepared by ball-milling raw materials for 3, 6, 9, and 12 h, respectively. The crystal structures, particle size, and morphologies of precursors and prepared La0.7Sr0.3MnO3±δ were characterized by XRD, laser particle size analyzer and SEM, respectively. It is found that La0.7Sr0.3MnO3±δ possessed large particle size by ball-milling raw materials for a long time. Results indicated that La0.7Sr0.3MnO3±δ, synthesized by ball-milling raw materials for 3 h, exhibited the optimal microwave absorption properties. The maximum reflection loss was −28.8 dB, and the −6 dB absorption bandwidth was 5.80 GHz.