Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er³⁺-substituted W-type barium ferrites Ba_1-xEr_x(Zn_0.3Co_0.7)₂Fe₁₆O₂₇ (x=0.00, 0.05, 0.10, 0.15, 0.20) were synthesized by polymer adsorbent combustion method. Samples were characterized by X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and network analyzer to investigate the relationships among Er³⁺ concentration, crystal structure, surface morphology and electromagnetic properties. All the XRD patterns showed pure phase of W-type barium ferrite when x=0.15, while the impurity phase of ErFeO₃ appeared when x=0.20. The pure W-type barium ferrite showed a hexagonal flake shape. In addition, the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz. It was indicated that the electromagnetic properties were significantly improved when Er³⁺ doping content was 0.10. The reasons were also discussed using electromagnetic theory. The optimized ferrite exhibited excellent microwave absorption performance. The maximum of reflection loss (RL) reached about ?27.4 dB and RL was below ?10 dB at the frequency range from 8.4 GHz to 18 GHz, when the thickness was 2.6 mm.