Fundamental Research On Heavy Matel/Magnetic Insulators Heterojunction Films And Anomalous Hall Devices

With the development of electronic information technology,and the demand of decreasing device size is becoming smaller,the spintronic devices have attracted extensive attention.The heavy metal/magnetic insulator heterostructure spintronic devices represented by YIG?yttrium iron garnet?have become a hotspot.The easy magnetization axis of YIG thin film tends to be parallel to the film surface,compared with the out-of-plane magnetic garnet thin film,the current density required to drive magnetization switching is still large.What's more,the thinner the garnet films are,the better for driving and measuring of spin current.Therefore,the preparation of garnet thin films with perpendicular anisotropy is beneficial to the development of device miniaturization,low damping,high storage density and high transmission rate in the future.This thesis is on the basis of existing theory,and analyze the theory of magnetic anisotropy of garnet films.A new kind of garnet single crystal films were prepared by LPE?liquid phase epitaxy?method.The garnet films with perpendicular anisotropy are promising in the application of spin logic and storage device.Firstly,the origin of magnetic anisotropy of garnet film is analyzed from the perspective of energy,which provid theoretical basis for the preparation of garnet films with perpendicular anisotropy by LPE method.The growth-induced anisotropy and stress-induced anisotropy of ganrent films are adjusting to overcome the shape anisotropy,which can turn the easy magnetic axis to perpendicular to the film.Secondly,the?TmBi?3?FeGa?5O12 garnet films with out-of-plane anisotropy were grown by RF magnetron sputtering,and the effects of films with different substrates were studied.On the one hand,the substrate with larger lattice constant increases the coercivity of the garnet films.On the other hand,the substrate with larger lattice constant increases the Kerr signal of the garnet film.Finally,we get an out-of-plane magnetic moment garnet film with 30nm thickness.What's more,?YBiLuCa?3?FeGe?5O12 garnet monocrystalline films are prepared by liquid phase epitaxial method as well,and the magnetic properties of the films were systematically studied.It was found that the growth-induced anisotropy was dominant in the magnetic anisotropy of the films,and the out-of-plane anisotropy of the films increased with the decreasing of the growth temperature.The minimum film thickness is 170 nm with damping coefficient 4.33×10^-4,ferromagnetic resonance linewidth?H=8.06 Oe@12 GHZ.Finally,Pt films were prepared on garnet films by magnetron sputtering to form heterostructure,and anomalous Hall effect of Pt/garnet films was studied.We studied the influence of the thickness of garnet film on the driving current,we found that the driving current corresponding to the thinner garnet film was small,which was significant for the development of low-loss spin logic devices in the future.