有序合金薄膜中结构、磁性及输运性质

有序合金薄膜的磁性,电学性质,以及电子结构能够在很大范围内得到调控，在自旋电子学器件领域具有举足轻重的地位。本项目将围绕L1(0) XPdPt（X=Fe, Co, Ni及其合金）和高自旋极化率哈斯勒合金薄膜及其异质结构的微结构、磁性、磁输运、以及自旋超快动力学性质开展研究。利用超高真空磁控溅射法制备高质量有序合金外延薄膜，研究工艺条件对微结构、磁性、电性等的影响。探讨自旋轨道耦合强度和费米面附近态密度对反常霍尔效应、各向异性磁电阻效应、反常能斯特效应等磁输运性质，磁性阻尼系数以及超快退磁等自旋超快动力学性质的调控机制。探索薄膜微结构等外在因素对磁输运和自旋超快动力学性质的影响机制。揭示哈斯勒合金薄膜界面各向异性机制。获得有序合金薄膜或者异质结，具备高自旋极化率、低磁性阻尼系数、垂直磁各向异性，以期为制备电流驱动磁化翻转磁随机存储器以及自旋场效应管等自旋电子学器件提供理想材料。

Since magnetic and magnetotransport properties, and electronic structure of ordered alloy films can be tuned greatly, they are of crucial importance in spintronics devices. In this project, we will fabricate L1(0) XPdPt(X=Fe, Co, Ni and their alloys) and high spin polarization Heusler alloy films and their heterostructures, and study their microstructural, magnetic, magentotransport, and spin ultrafast dynamics properties. Fabrication condition will be optimized to obtain the high quality epitaxially grown L1(0) XPdPt(X=Fe, Co, Ni and their alloys), Heusler alloy films and their bilayers. Effects of fabrication condition on microstructural, magnetotransport, and spin dynamics properties are studied. Effects of spin orbital coupling and density of states near Femi surface on the intrinsic contributions of magnetostransport including anomalous Hall effect, anisotropic magnetoresistance, and anomalous Nernst effect, and spin ultrafast dynamics properties including magnetic damping parameter and ultrafast demagnetization are revealed. Extrinsic contributions of the microstructure to the magnetotransport and spin ultrafst dynamics properties will also be uncovered. Mechanism of the interface anisotropy in Heusler alloy films will be revealed. Finally, ideally perpendicularly magnetized ordered alloy films or heterostructures with low magnetic damping parameter, suitably low perpendicular magnetic anisotropy, and high spin polarization will be obtained for design and fabrication of spin transfer torque magnetic random access memory devices and spin field effect transistors.