Temperature dependence of multi-jump magnetic switching process in epitaxial Fe/MgO (001) films

Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO (001) films is investigated by magnetoresistance measurements. When the temperature decreases from 300 K to 80 K, the measured three-jump hysteresis loops turn into two-jump loops. The temperature dependence of the fourfold in-plane magnetic anisotropy constant K₁, domain wall pinning energy, and an additional uniaxial magnetic anisotropy constant K_U are responsible for this transformation. The strengths of K₁ and domain wall pinning energy increase with decreasing temperature, but K_U remains unchanged. Moreover, magnetization reversal mechanisms, with either two successive or two separate 90° domain wall propagation, are introduced to explain the multi-jump magnetic switching process in epitaxial Fe/MgO(001) films at different temperatures.