Microwave Absorption Properties of Ba–M Hexaferrite with High Substitution Levels of Mg–Ti in X Band

Abstract

BaFe12−x Mg0.5x Ti0.5x O 19 nanoparticles were synthesized by using a modified sol–gel method. In order to investigate electromagnetic (EM) wave absorption properties of Mg–Ti-substituted barium hexaferrite nanoparticles, composites including ferrite (filler) and acrylic resin (matrix) with a weight ratio of 70:30 (ferrite/resin) were prepared. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), alternative gradient force magnetometer (AGFM), and vector network analyzer (VNA) were used to investigate the morphological, structural, magnetic, and EM wave absorption characteristics of the samples. The XRD results indicated that by the modified sol–gel synthesis method, the substituted compounds were a single-phase hexagonal ferrite for x=0 to x=5. FE-SEM images showed that the particle sizes were almost in a range of 35–50 nm. With an increase in the substitution level from x=0 to x=5, the maximum magnetization and coercivity decreased from 53.2 emu/g and 4900 Oe to 8.6 emu/g and 50 Oe, respectively. The reflection loss patterns of the samples showed that EM wave absorption was improved with an increase in the substitution levels, and the effect of substitution level on the intensity of EM wave absorption was discussed. The best reflection loss value was −55 dB obtained by the sample with x=5 in the frequency of 10.8 GHz. The results indicated that the composites containing Mg–Ti-substituted barium hexaferrite nanoparticles with high substitution levels synthesized by the modified sol–gel process can be considered as suitable EM wave absorbers in X-band applications.