Effect of annealing on the characteristics of Au/Ni₅₀Fe₅₀ bilayer films grown on glass

Hao Qian1), Hong Qiu1), Xiaobai Chen1,2), Yue Tian1), Ping Wu1), Fengping Wang1), and Liqing Pan1) 1) Applied Science School, University of Science and Technology Beijing, Beijing 100083, China 2) Department of Mathematics and Physics, Beijing Technology and Business University, Beijing 100037, China

摘 要：Sputter-deposited Au/Ni₅₀Fe₅₀ bilayer films were annealed in a vacuum of 5×10^-4 Pa at 523 to 723 K for 30 or 90 min. The characteristics of the bilayer films were determined by Auger electron spectroscopy, field emission scanning electron microscopy, X-ray diffractometry, a four-point probe technique, and an alternating gradient magnetometer. When the annealing temperature and time reached 723 K and 90 min, Ni and Fe atoms markedly diffused into the Au layer. The grain size of the Au layer did not change markedly with the annealing condition. As the annealing time was 30 min and the annealing temperature exceeded 573 K, the resistance of the bilayer film increased with increasing the annealing temperature. Furthermore, the resistance of the bilayer film annealed at 723 K for 90 min was lower than that of the bilayer film annealed at 723 K for 30 min. All the bilayer films showed magnetic hysteresis loops. The as-deposited bilayer film showed a hard magnetization. The bilayer film represented an easy magnetization with increasing the annealing temperature. The Au/Ni₅₀Fe₅₀ film that annealed at 723 K for 90 min had the lowest saturation magnetization.

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