Study On The Four-Corner Distortion And Interlayer Exchange Coupling Of FeCo-Based High-Frequency Soft Magnetic Film

Modern electronic components tend to be miniaturized and integrated,and high-frequency soft magnetic films can meet the application requirements of contemporary electronic devices for miniaturization and processing speed,such as applying them to miniature inductors.In practical applications,due to the advantages of high saturation magnetization,high permeability,low coercivity,and high natural resonant frequency of soft magnetic films,the study of soft magnetic films has become a hot spot in the field of magnetics research.In the current research,FeCo-based soft magnetic films have excellent high-frequency magnetic properties,and the frequency of ferromagnetic resonance of self-biased high-frequency soft magnetic films has reached as high as 20 GHz,but it still cannot meet the need of extremely high frequency devices,so it is necessary to use new means to increase the frequency of the thin film.In this paper,through the magnetocrystalline anisotropy of FeCo nanocrystals and the interlayer exchange coupling between the trilayer films of symmetrical structure,high-frequency soft magnetic films with frequencies reaching extremely high frequency bands are prepared to meet the needs of electronic components in the information age.In this paper,the magnetocrystalline anisotropy of the nanocrystalline thin films enhanced by the tetragonal distortion of FeCo crystals in a certain thickness range is used as the ferromagnetic resonance driving force of the soft magnetic thin films,so that the ferromagnetic resonance frequency of the thin films is as high as 42.7 GHz.A series of work has been carried out on the preparation conditions of the samples,single-layer film samples with different crystal orientations,and ferromagnetic/non-ferromagnetic/ferromagnetic（FM/NM/FM）sandwich structures.The main contents and results are as follows:（1）Explore the preparation process of FeCo/MgAl₂O₄ single crystal thin films by the technology of the magnetron sputtering.Changing the sample deposition temperature and the sputtering gas pressure to explore the best conditions for preparation.The specific preparation conditions are as follows:the substrate is placed in a vacuum chamber,the vacuum pressure is lower than5×10^-5 Pa,the sample deposition temperature is 300℃,the sputtering pressure is 0.3 Pa,and the sputtering power is 40 W.（2）FeCo nanocrystals were epitaxially grown on MgAl₂O₄（110）and MgAl₂O₄（100）,and through the performance characterization,the critical thickness of the samples with tetragonal distortion was summarized.Extremely high frequency are reached,resulting in a maximum frequency of 42.7 GHz within the measurement threshold.The nanocrystalline thin films obtained by epitaxy on two kinds of the single crystal substrates have different symmetries,and judged the reason for this phenomenon.（3）Explore the preparation process of FeCo/Ru/FeCo/MgAl₂O₄（100）trilayer film,and obtain the best preparation conditions by changing the thickness of the intermediate non-ferromagnetic layer.Under the condition of the t _Ru=3?,the effect of different ferromagnetic layer thicknesses on the ferromagnetic properties of FeCo（200）/Ru/FeCo（200）/MgAl₂O₄（100）was investigated,and the critical thickness of the sandwich-structured films for tetragonal distortion was obtained.Comparing the results of the trilayer film with the single-layer film,it is concluded that the interlayer exchange coupling between the two ferromagnetic layers has an adverse effect on the increase of frequency.