Microstructural evolution and enhanced magnetic properties of FeCoNiZr_x medium entropy alloy films

Medium/High entropy alloys (M/HEAs) based on the FeCoNi system have gained significant attention due to their outstanding magnetic and electrical properties. In this study, the FeCoNiZr_x (x = 0, 0.2, 0.4, 0.6, 0.8, 1) MEA films were prepared using the magnetron sputtering method. The effect of Zr on the structure and soft magnetic properties is studied. As the Zr content increases, the films transform from the face-centered cubic (FCC) phase to the amorphous phase. This study shows that FeCoNiZr_0.4 film exhibits excellent combined properties, including a high magnetization saturation (Ms) of 1127.8 emu/cm³, a minimum coercivity (Hc) of 0.96 Oe, and a high resistivity of 147 μΩ·cm, which is superior to the Permalloy and soft magnetic materials reported in other articles. Combined structural analyses show that the FeCoNiZr_0.4 film has the finest particle size, amorphous structure, and continuous and uniform magnetic domains, decreasing the pinning effect on magnetic domains. These results enhance the magnetic properties of FeCoNiZr_0.4 film.