Magnetism and Microwave Absorption Properties of Fe3O4 Microflake–Paraffin Composites Without and With Magnetic Orientation

Abstract

We have synthesized thin Fe3O4 microflakes by a simple hydrothermal method and prepared Fe3O4 microflake–paraffin composites without and with magnetic orientation using the method of simple ultrasonic mixing and rotating samples in a magnetic field. X-ray diffractometer, Mossbauer spectrum, scanning electron microscope and vibrating sample magnetometer were used to characterize the samples. The complex permittivity and permeability of Fe3O4 microflake–paraffin composites without and with magnetic orientation were measured in the frequency range of 0.1–18 GHz by a vector network analyzer using a coaxial method. The reflection loss (RL) was calculated by the measured electromagnetic parameters using transmission line theory. The measurement of electromagnetic parameters shows that magnetic orientation makes the complex permittivity and permeability increase. The calculated RL shows that the Fe3O4 microflake–paraffin composite with magnetic orientation has enhanced microwave absorption properties in the frequency range of 1–3 GHz and the thickness range of 2.9–3.5 mm, indicating that the Fe3O4 microflake–paraffin composite with magnetic orientation is a promising thin microwave absorption material in the L-S band.