Interfacial structure/chemistry of spintronics devices with Heusler alloy electrodes

以半金属Heusler合金为电极的自旋电子器件界面结构/化学性质关系的研究。除了用于隧道磁阻（TMR）器件的Heusler合金和氧化物屏障之间的界面外，还将特别关注Heusler合金与金属间隔材料和半导体的接触，以开辟电流垂直喷射器-平面巨磁阻（CPP-GMR）和自旋注入器的新应用。通过溅射沉积和分子束外延制备了功能TMR和GMR层结构。选择不同的阻挡层和间隔层材料以及Heusler合金的成分，以确定对界面结构、顺序和各自界面的局部化学的影响。为了明确界面偏析的影响，在分子束外延中，通过控制粉尘直接改变界面的局部组成。这些制备的结构将在适当的热处理后进行电和磁表征。为了检测界面成分的最小变化，将应用最先进的激光辅助原子探针断层扫描。采用高分辨率和解析电镜对金属间Heusler合金的有序态和形貌进行了表征。

Discovering the structure/chemistry property relationship of interfaces in spintronic devices comprising half metal Heusler alloys as electrodes. Beside the interface between Heusler alloys and oxide barriers used in tunneling magnetoresistance (TMR) devices, special attention will be paid to Heusler alloys in contact to metallic spacer materials and semi-conductors in order to open up new applications in current-perpendicularrto-plane giant magnetoresistance (CPP-GMR) and spin-injectors. Functional TMR and GMR layer structures are produced by sputter deposition and molecular beam epitaxy. Selected materials of barriers and spacer layers and the composition of the Heusler alloys will be varied to determine the effect on interfacial structure, order and local chemistry of the respective interfaces. To clarify the effect of interface segregation, the local composition of interfaces will be directly modified by controlled dusting in molecular beam epitaxy. These prepared structures will be electrically and magnetically characterized after suitable heat treatment. To detect smallest variations of interfacial composition, state-of-the-art laser-assisted atom probe tomography will be applied. High resolution and analytical TEM will be used to characterize ordering state and morphology of the intermetallic Heusler alloys.