Effects of Sm-doping on microstructure, magnetic and microwave absorption properties of BiFeO3

Abstract

In this paper, polycrystalline samples of Bi1–xSmxFeO3 (x = 0, 0.05, 0.1, 0.15) were successfully synthesized by sol-gel method. The effects of Sm concentration on the crystal structure, morphology, chemical states, magnetic properties and microwave absorption performance were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), a vibrating sample magnetometer (VSM) and a Vector network analyzer (VNA), respectively. The results show that the rare earth Sm doping causes the crystal structure to change. When x ≤ 0.1, Bi1–xSmxFeO3 is the distorted rhombohedral structure with space group R3c. With the increase of Sm doping amount to x = 0.15, the phase structure of Bi1–xSmxFeO3 changes from rhombohedral structure to cubic structure with the space group Pm3¯m. The particle size decreases with the increase of the Sm doping amount. The analysis results show that Sm doping can effectively reduce the oxygen vacancies and significantly improve its magnetic properties. The results exhibit that moderately doped rare earth Sm element can effectively improve microwave absorption properties of Bi1–xSmxFeO3 powders. When Sm doping amount of x is 0.1, the Bi0.9Sm0.1FeO3 compound has good microwave absorption performance, and the minimum reflection loss value of Bi0.9Sm0.1FeO3 powder reaches about −32.9 dB at 11.7 GHz, and its effective absorption bandwidth (RL < −10 dB) is 2.6 GHz with the optimal matching thickness of 2.0 mm.