Study The Magnetization Of The Magnetic Properties Of The Thin Film System

Nowadays, when science and technology are developing rapidly, Spintronic devices, based on the magnetic material, are widely used in all aspect of life. Magnetic film structure has become the most common structure of magnetic devices such as the magnetic read-write head, magnetic sensor, etc, because of its optics, mechanics and electromagnetism characteristics. So, research on magnetic properties of single, double or multilayer magnetic thin film become the focus of attention.Among the factors that influence the magnetic properties of magnetic thin film system, stress is common and inevitable. Stress in magnetic film structure mainly comes from an artificial stress and the residual stress during the process of preparation. The artificial stress can be used to control the magnetic properties of the the magnetic thin film system, and the residual stress need us to understand and avoid. In this paper, we studied how the kind of non-uniform stress which conform to the gaussian distribution on the single magnetic thin films. And how the stress caused by lattice mismatch between film and substrate influence on the properties of FM/AFM bilayer film.In chapter1, we introduced magnetism of material, history of magnetics, the spin valve films system, and Exchange Bias-one of the most important phenomena in the spin valve films system. In chapter2, we introduced Monte-Carlo method(Monte Carlo) and Free energy Variational method(Free energy variational), which are mainly used in the research methods in this paper.In chapter3, we analyze how the non-uniform stress-derived from the deformation of substrate, a kind of very popular method-affect the magnetic properties of the the magnetic thin film system. Then, we also build up a stress model conform to the gaussian distribution to calculate, coming to some interesting results, comparing with the experimental results.In chapter4, we analyze how the stress, which caused by lattice mismatch or what other factors like that, affect the Coercive Field and Exchange Bias of the FM/AFM bilayer film system. The results shows that stress can influence the strength of Coercive Field and Exchange Bias by changing the Equivalent anisotropy of the FM/AFM bilayer film.Then, compare the calculation results with the experimental results.