Effect of deposition temperature on SrFe₁₂O₁₉@carbonyl iron core-shell composites as high-performance microwave absorbers

The SrFe₁₂O₁₉@carbonyl iron (CI) core-shell composites used in microwave absorption are prepared by the metal-organic chemical vapor deposition (MOCVD). The x-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, and vector network analyzer are used to characterize the structural, electromagnetic, and absorption properties of the composites. The results show that the SrFe₁₂O₁₉@CI composites with a core-shell structure could be successfully prepared under the condition: deposition temperatures above 180 ℃, deposition time 30 min, and gas flow rate 30 mL/min. The electromagnetic properties of the composites change significantly, and their absorption capacities are improved. Of the obtained samples, those samples prepared at a deposition temperature of 180 ℃ exhibit the best absorption performance. The reflection loss of SrFe₁₂O₁₉@CI (180 ℃) with 1.5 mm-2.5 mm in thickness is less than -10 dB in a frequency range of 8 GHz-18 GHz, which covers the whole X band and Ku band.