The influence of Nd substitution in Ni–Zn ferrites for the improved microwave absorption properties
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Affiliation of Author(s):材料科学与技术学院 Journal:Ceram Int Abstract:Nanocrystalline Ni–Zn ferrites with different neodymium contents (Ni0.5Zn0.5NdxFe2-xO4) were synthesized by sol-gel route combined with self-propagating combustion (SPC) method. The presence of surface functional groups, crystal structure and morphology of the samples were studied by FT-IR, XRD and SEM. The results show that the prepared samples are composed of spinel phase under the condition of low neodymium content, like the pure Ni–Zn ferrite. While neodymium oxide appears after the content of Nd3+ exceeds a certain limit (x > 0.04) and there exist two phases in the ferrite. The results of vibrating sample magnetometer (VSM) and vector network analyzer (VNA) show that adjusting the content of Nd is significant in improving the dielectric properties and microwave absorption capacity of the materials, specifically at low frequencies. When x < 0.04, the enhancement of dielectric loss ability of spinel ferrites by doping Nd3+ is the dominant factor affecting microwave absorption ability of samples. The secondary phase Nd2O3 hardly appears under this condition, thus the weakening effect of Nd3+ addition on magnetic loss ability is not obvious. When x = 0.04, the optimal absorption peak of the material reaches −20.8 dB at 4.4 GHz with a thickness of 8.5 mm and the effective absorption bandwidth (RL < −10 dB) was 3.2 GHz. On the contrary, when x > 0.04, the magnetic loss ability decreases rapidly (e.g., Ms decreases from 82.47 emu/g to 59.77 emu/g). Meanwhile, the dielectric loss increases slowly and the microwave absorption capacity decreases. © 2019 Elsevier Ltd and Techna Group S.r.l. ISSN No.:0272-8842 Translation or Not:no Date of Publication:2020-01-01 Co-author:Qian, Kun,Lin, Haiyan,Zhou Jintang,Haidry, Azhar Ali,Qi, Tongbaihui,Chen, Wenjing,Guo, Xinlu Correspondence Author:Yao Zhengjun Date of Publication:2020-01-01
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