The Anomalous Hall Effect And Magnetic Properties Of CoMn And FeCo Alloy Films

In recent years,due to its abundant physical connotation,the anomalous Hall effect(AHE)has received extensive attention.AHE mainly includes three mechanisms:intrinsic mechanism which is related to Berry curvature of occupied band,skew scattering which is related to asymmetric scattering,and side-jump which is related to asymmetric displacement.In experiments,these three mechanisms all contribute to AHE,and people have been trying to distinguish their contributions,resulting in a series of scaling relations.In 2009,Jin et al.(Phys.Rev.Lett.103,087206(2009))proposed the Tian-Ye-Jin(TYJ)relationship,which distinguishes the contributions of the three mechanisms in experiments and is applicable to many systems.Subsequently,when the AHE of the high-quality Fe single crystal films grown on the MgO(001)substrate was scaled,it was found that the TYJ relational expression was not applicable.In 2015,Hou et al.(Phys.Rev.Lett.114,217203(2015))proposed a scaling relationship based on multiple scattering through theoretical derivation,which can accurately scale the AHE of high-quality Fe single crystal films.This relationship has been applied in some systems,however,for different systems,the conversion of the dominant mechanism of competition between different scattering sources has not been tudied in depth.In order to explore the transformation of competitive relationship between different scattering sources,we can use high-quality epitaxial metal alloys to perform related experiments.The focus of this paper is on the application of the AHE scaling relations and further research on its related properties under the above discussion,this paper mainly has the following three parts:(1)We grew a series of Co_100-xMn_x thin films on MgO(001)substrate by molecular beam epitaxy(MBE),and characterized their structure and magnetic properties.It was found that the deviation of magnetic properties from Slater-Pauling curve in Co_100-xMn_xthin films with low Mn concentration should be attributed to the structural transformation.On this basis,a series of Co₉₀Mn₁₀ films were grown at different substrate temperatures,and the nature of the transformation was explored by structural characterization and scaling of AHE.Here,the anomalous Hall effect is used as a special method to explain the relationship between the structure and transport properties of Co₉₀Mn₁₀ thin films,and the contribution of intrinsic and extrinsic mechanisms of Co₉₀Mn₁₀ thin films is distinguished by the TYJ relation.(2)We have grown a series of Fe Co films with thickness d?4.1 nm on MgO(001)substrate by MBE,we have characterized the structure of these samples,and measured the magnetic and transport properties.We used the existing scaling relation to scale the AHE of Fe Co films with thickness d?4.1 nm,and found that the relation proposed by Hou et al.was more appropriate.Through the results obtained by fitting,we found that the competing contributions of different scattering sources to AHE change correspondingly with the increase of film thickness,which is attributed to the fact that the dynamic scattering gradually occupies the dominant position in the competition between dynamic scattering and static scattering with the increase of film thickness.(3)We have grown some Fe Co films with a thickness of 1.0 nm?d?3.0 nm on MgO(001)substrate,and characterized its structure.We found that the RHEED stripes in the Fe Co film with d=1.0 nm are very clear,and even for Fe Co film with d=1.3 nm,there is a relatively weak diffraction peak in the out-of plane XRD curve,indicating that the quality of Fe Co film growth is good.By fitting the longitudinal resistivity of Fe Co films,we found that the longitudinal resistivity is mainly affected by weak localization and/or electron-electron interaction at low temperature,and the contribution of weak localization to the skew scattering mechanism of AHE is non-zero.By using the TYJ relationship to scale the AHE of Fe Co films,we find that the AHE of1.6 nm?d?3.0 nm Fe Co films is dominated by the contribution of the intrinsic mechanism.