Magnetic properties and microwave absorption of Ni0.7Zn0.3A0.05Fe1.95O4 (A = La, Ce, and Nd) powders within the range of 2–18 GHz

Abstract

Ni0.7Zn0.3A0.05Fe1.95O4 (A = La, Ce, and Nd) powders were obtained by the sol-gel combustion technique. The phase composition, microstructure, and electromagnetic properties of La3+, Ce3+, and Nd3+ substituted Ni0.7Zn0.3Fe2O4 were investigated. Compared with the Ni0.7Zn0.3Fe2O4 ferrite, the saturation magnetization of substituted Ni0.7Zn0.3Fe2O4 powders decreases due to the reduction of the super-exchange interaction by the substitution of La3+, Ce3+, and Nd3+at the Fe site. Furthermore, the enhanced dielectric constant of the substituted Ni0.7Zn0.3Fe2O4 ferrites prompts to the formation of good impedance matching and thereby improving the microwave absorption performance. The best reflection loss of Ni0.7Zn0.3Ce0.05Fe1.95O4 ferrite is −17.5 dB at 13.8 GHz, and the corresponding absorption bandwidth (RL ≤ 5 dB) can be achieved 10.9 GHz. These results suggested that the Ni0.7Zn0.3Ce0.05Fe1.95O4 ferrite is a potential composite for electromagnetic applications, particularly for broadband microwave absorption.