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)₂Fe₁₆O ₂₇ (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.