Hysteretic Behavior Of The Dynamic Permeability On A Fe-Co Thin Film

With the development of the modern science and technology, people are living in a gradually electronized world, and the development speed of electronic products is accelerating fast by reason of the increasingly higher demand. Nowadays electronic equipment like mobile phones and computers update rather rapidly, burgeoning wearable devices emerge and become more and more popular, which raise strict requirements for basic manufacturing and the electronic components’ development. The future direction of electronic equipment’s development is to be more multifunctional, co-related and miniaturized, therefore, investigation of integrated circuit technique is currently attracting worldwide attention which rapidly promote the miniaturization of devices. It raises the need for the miniaturization of magnetic devices. However, conventional 3D magnetic powder materials are quite hard to be applied in the new miniaturized devices. As a new type of magnetic material, soft magnetic thin film plays an important transitional role between 3D powder materials and low-dimensional nano-materials. With high permeability in GHz band, the soft magnetic thin film has become one of the research hotspots.There are two directions for research on soft magnetic thin film. On the one hand, we can e seek methods for depositing thin film with better soft magnetic properties by experiment. On the other hand, we can explore the connection between the internal microscopic structure and macroscopic property to extend the theory further. Both the directions are based on the basic research like hysteresis loop and magnetic spectrum. The microscopic theory is integrated with depositing and characterization, and hysteresis correlation between hysteresis loop and magnetic spectrum of ferromagnetic thin film is found in this paper. It provides a new analysis method for the study of the ferromagnetic film’s magnetic structure, which has an important significance for magnetic thin films based study of high frequency magnetic device. Our main research results are shown as following:A 150-nm-thick Fe-Co film have been deposited by means of RF Magnetron Sputtering, the hysteresis loop containing coercivity have been measured and the dynamic properties have been surveyed through permeability measurements in the 0.5GHz to 8GHz range, within an applied field in the easy direction. The results depend not only on the external field, but also on the orientation of the magnetization compared to the field. If they are in the same direction, the decrease of the external field will lead to the decrease of the resonance frequency. Otherwise, the resonance frequency changes differently within different range of the applied field according to the magnetic hysteresis shown in the ferromagnetic films. The phenomenon can be explained by ferromagnetic resonance equations and the ratio of magnetic moments in the opposite direction has been calculated.