Study Of The High Frequency Magnetic Properties Of Ferromagnetic Microstructured Multilayer Films

With the increasing degree of integration of electronic devices,electromagnetic noise induced by conduction interference and electromagnetic radiation interference deteriorate the properties of devise,anti-electromagnetic interference can not be ignored.There are two problems for soft magnetic thin film to used in anti-electromagnetic interference field.The surface resistivity of the soft magnetic thin film will lead to the microwave impedance mismatch,which would seriously affect the microwave performance of electronic devices.The narrow resonant frequency band of soft magnetic thin film is not applicable for anti-electromagnetic interference device with wide band.In this article,we propose soft magnetic films based on graphical and multi-layer design.Because of the isolation layer,resistivity of multilayer films is improved and resonant frequency band is widened.And the use of graphical introducted the shape anisotropy,the resonant frequency is improved.Combined with miro-magnetic and magnetic resonance loss theory,this article design and prepared the microstructured multilayer films,analysis the microwave loss mechanisms.Be aimed to improve the resistivity of soft magnetic thin film with high resonant frequency and broadband which would providethe technological foundation for the study of anti-electromagnetic interference devices.The main research work is as follows:1.Study on magnetic properties of continuous multilayer films（1）We produced FeCoB/SiO₂（xnm）/FeCoSiB multilayer films to study the effect of isolation layer on the magnetic properties of multilayer films.The result shows that isolation layer with thickness of 7nm,that can effectively decouple Fe CoB layer and FeCoSiB layer.The dynamic magnetic response of magnetic layers can be observed double resonance peak,this means,the isolation layer can build a high frequency magnetic response superposition model between the magnetic layers of the multilayer film.（2）We produced FeNi/SiO₂/FeCoSiB multilayer films and FeNi/SiO₂/FeCoB multilayer films,The dynamic magnetic response of these films can be observed double resonance peak.This verified that isolation layer can build a high frequency magnetic response superposition model between the magnetic layers of the multilayer film is applicable to FeNi.2.Study on magnetic properties of multilayer films which was composed of continuous FeNi film and graphic FeCoSiB film.The dynamic magnetic response of this films can be observed double resonance peak at 1.4GHz and 2.4GHz.The second resonance peak can be adjusted by adjusting the thickness of the top laye FeCoSiB striped film.3.Study on magnetic properties of microstructured multilayer films,we produced FeCoSiB striped multilayers.FeCoSiB striped multilayers was compounded by FeCoSiB striped films with different thickness.The dynamic magnetic response of FeCoSiB striped films can be observed double resonance peak at 4.5GHz and 7.5GHz.In this study,we broadened the resonance peak at high frequency,The second resonance peak can be adjusted by adjusting the thickness of the top laye FeCoSiB striped film also.