Effect of Cu on microstructure, magnetic properties of antiperovskite nitrides Cu_xNFe_4−x

For soft magnetic materials, especially new intermetallic compounds, some good soft magnetic properties, such as high permeability, low power loss, as well as superior DC-bias properties, will determine their prospects for application. In this paper, we report soft magnetic properties of Cu_xNFe_4−x, prepared by a new synthetic method. Although the saturation magnetization of the samples is slightly lower than that of Fe₄N due to Cu doping, various other experimental results clearly provide evidence that the Fe substitution by Cu leads to the optimization and improvement of soft magnetic properties in Fe₄N. With increasing Cu content, the permeability increases and power loss reduces from 1064.5 mW/cm³ for x = 0.1 to 679 mW/cm³ for x = 0.5 at H = 8 A/m, f = 1000 kHz. Additionally, the value of DC-bias (μ_H/μ_H=0) rises above 82% at H = 100 Oe, implying a superior DC-bias properties. More importantly, with the increases of x content, the value of μ_H/μ_H=0 increases and reaches 87% for sample x = 0.5 at H = 100 Oe. The improvement of soft magnetic properties of the Fe-based antiperovskite Cu_xNFe_4−x is encouraging for future applications as functional materials.