The Research On Strain-insensitive Flexible Magnetic Film

Magnetic materials including bulk and film have its own property, its magnetic property will be changed if applied factors including stress or light. In the past research, stress is regard as an effective method to change the property of magnetic materials. Studying the law of stress influence the property of magnetic materials is an important work to speed up development of the flexible electronics.Magnetic anisotropy is a fundamental property of magnetic materials determining the easy magnetization axis, which is essential for many devices such as magnetic recording, magnetic sensors, etc. Magnetic materials with different magnetic anisotropy are needed for various applications. So it is important to finding a way to tune magnetic anisotropy of magnetic materials. On the other hand, designing a method to fabricate continuing magnetic films with controllable magnetic anisotropy are desired to reduce their producing cost. In our work, we use amorphous magnetic film deposition on flexible substrate, including two major works:1. We introduce a method to grow amorphous Co40Fe40B20 (CoFeB) thin film, which is widely used in spintronic devices due to its highest spin polarization, on the bending flexible substrates. A large uniaxial anisotropy will be induced in films due to a compressive strain along one axis after fabrication. The magnetic anisotropy of CoFeB is strongly dependent on the curvature radius, the thickness both of the film and the substrate. These results can be explained by stress-induced magnetoelastic anisotropy, showing that magnetic anisotropy can be effectively tuned in amorphous magnetic films on the flexible substrates. Based on this way of tuning magnetic anisotropy, we design a method, combining the roll-to-roll continue printing technique, to grow the large scale of flexible magnetic films with controllable magnetic anisotropy.2. We prepare the magnetic film and the magnetic anisotropy is induced by bending growth and magnetic field induced. When applied different stress on the magnetic film, the magnetic anisotropy will have a little change. The way we design to preparation the magnetic film will insensitive to the stress.