Preparation And Magnetic Study Of Soft Magnetic Films In FeCoC System

With the rapid development of electronic information,aerospace,new energy and other fields,soft magnetic materials are widely concerned and used in cores,generators,transformers,sensors and other devices because of their high saturation magnetization strength,low coercivity and magnetic loss.At the same time,soft magnetic materials have started to develop towards miniaturization and thin film.For example,Co Fe B soft magnetic films are widely used in magnetic memory and magnetic sensors,but their thermal stability performance is insufficient,so it is important to further investigate new soft magnetic film materials with excellent soft magnetic properties and thermal stability performance.In this thesis,a series of FeCoC soft magnetic thin film materials were prepared using electron beam evaporation vacuum coating to investigate the effects of carbon content,heat treatment conditions,growth temperature,and preparation process on the structure and properties of the samples.The main results obtained are as follows.(1)The FeCoC soft magnetic thin film materials were prepared using alternating evaporation method and co-evaporation method,respectively,and it was found that the use of layer-by-layer alternating evaporation method could prepare films with good denseness,low coercivity,high saturation magnetic induction strength,and excellent soft magnetic properties.(2)The structure and properties of FeCoC soft magnetic films vary regularly with the change of C content.When the C content is less than 3.04 wt.%,C doping refines the grain size and leads to an increase in the coercivity of the film;when the C content is greater than 3.04 wt.%,C doping decreases the crystallinity of the FeCo phase,leading to a decrease in the coercivity and a decrease in the saturation magnetization strength;when the C content is 8.59 wt.%,the coercivity of the FeCoC soft magnetic film decreases to a very small value(16 Oe).Therefore,the C doping greatly improves the soft magnetic properties of the films,which makes the FeCoC soft magnetic films have greater potential for applications in inductors,wave absorbing materials,magnetic recording materials,etc.(3)When the growth temperature was increased from 100 ? to 300 ?,the coercive force of FeCoC0.2 soft magnetic film decreased to 16 Oe and the surface morphology was flatter,indicating that a reasonable increase in the growth temperature of the film can reduce the thermal stress in the film,which is beneficial to the preparation of the film and the improvement of the soft magnetic properties;while the coercive force of FeCoC0.3 increased with the increase of the growth temperature,indicating that the C content The coercivity of FeCoC0.3 increases with the increase of growth temperature,which indicates that the increase of C content can weaken the influence of thermal stress in the film and make the coercivity of the film decrease,while the saturation magnetization intensity is basically unchanged.(4)After annealing at 500 ? for 1 h,the surface morphology of FeCoC films still has high uniformity and the coercivity increases to 140 Oe(comparable to that of binary FeCo films),indicating that the FeCoC soft magnetic film material has certain thermal stability performance.