Soft Magnetic Properties of High-Bs FeTa-N-O Films

Magnetic thin films of FeTa-N-O were prepared by using facing-target type dc magnetron sputtering in Ar+N2+O2 plasma. The magnetic and structural properties were investigated as a function of the flow rates of the O2 and N2 introduced into the argon atmosphere. A high Bs (19 kG) and soft magnetic properties (Hc¿0.3 Oe, ¿¿3000) were obtained for a wide range of O2 and N2 flow rates, and were retained after high-temperature (600°C) annealing. X-ray diffraction patterns of ¿-Fe (110) revealed that the soft magnetic films consisted of fine grains. The addition of Ta and N2 together with 02 in small amounts was highly effective for improving the soft magnetic properties and thermal stability. It decreased the post-annealing magnetic anisotropy and prevented the growth of ¿-Fe grains.