Sun, Hongli; Zhao, Xupeng; Han, Rongkun; Zhang, Chen; Liu, Lei; Qin, Hongrui; Xie, Zhicheng; Deng, Huixiong; Pan, Dong; Wei, Dahai; Zhao, Jianhua Source: Applied Physics Letters, v 124, n 10, March 4, 2024;

Abstract:

Rare-earth-free perpendicularly magnetized L10-MnxAl alloy holds promise for low-cost permanent magnets and high-performance spintronic devices. In this Letter, we report a large-scale modulation of perpendicular magnetic anisotropy (PMA) in MnxAl films by changing the composition x. Through utilizing a lattice-matching B2-CoGa underlayer and optimizing growth conditions, the 30-nm-thick MnxAl films can maintain excellent PMA in a wide composition range (0.7 ≤ x ≤ 3). Meanwhile, the crystalline structure and magnetic properties exhibit a strong dependence on the composition with saturation magnetization changing from 443.75 to 20.52 kA/m, coercivity from 0.22 to 5.38 T, and PMA constant up to 1.34 × 10 J/m. Combining experimental and calculation results, we confirm the existence of ferrimagnetic-like state in MnxAl under Mn-rich conditions. Further experiments validate the continued efficacy of our method in ultrathin MnxAl films, and spin-orbit torque induced magnetization switching has been realized. These results offer valuable insights into the modulation of fundamental properties and promote the potential application of MnxAl alloy.

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