Bending Strain Tailored Magnetic and Electronic Transport Properties of Reactively Sputtered γ΄-Fe4N/Muscovite Epitaxial Heterostructures toward Flexible Spintronics.

Research paper by Xiaohui X Shi, Mei M Wu, Zhengxun Z Lai, Xujing X Li, Peng P Gao, Wenbo W Mi

Indexed on: 29 May '20Published on: 29 May '20Published in: ACS Applied Materials & Interfaces


The strain modulation on the magnetic and electronic transport properties of the ferromagnetic films is one of the hot topics due to the practical applications in flexible and wearable spintronic devices. However, the large strain-induced saturation magnetization and resistance change is not easy to achieve because most of the ferromagnetic films deposited on flexible substrates are polycrystalline or amorphous. Here, the flexible epitaxial γ΄-Fe4N/mica films are fabricated by facing-target reactive sputtering. At a tensile strain with a radius of curvature (ROC) of 3 mm, the saturation magnetization (Ms) of γ΄-Fe4N/mica film is tailored significantly with a maximal variation of 210%. Meanwhile, the magnetic anisotropy was broadly tunable at different strains, where the out-of-plane Mr/Ms at a tensile strain of ROC=2 mm is 6 times larger than that at unbent state. Besides, the strain-tailored longitudinal resistance Rxx and anomalous Hall resistivity ρxy appear, where the drop of Rxx (ρxy) reaches 5% (22%) at a tensile strain of ROC=3 mm. The shift of nitrogen position in γ΄-Fe4N unit cell at different bending strains plays a key role on the strain-tailored magnetic and electronic transport properties. The flexible epitaxial γ΄-Fe4N films have the potential applications in magneto- and electro-mechanical wearable spintronic devices.