Spin-Polarized Vacuum Tunneling Study

该项目将在超高真空环境中将自旋极化隧道方法与扫描隧道显微镜(STM)的一些技术相结合。这些技术将用于探测超导和磁性材料的表面磁性。这项研究将包括超导体中自旋轨道和磁散射的低温研究，正常金属中的磁性杂质，以及定向单晶铁磁体的隧道测量。该项目的一部分将涉及对STM和自旋极化隧道SSTM设备的运行至关重要的超导和铁磁尖端的继续开发。铁磁到铁磁的隧道测量将在温度高达300K的情况下进行，使用各种材料和调制技术。STM技术最初将用于将隧道尖端定位在隧道距离内的适当位置。稍后，将在单个杂质或反铁磁体的研究中研究空间分辨率的极限。这些结果将与理论进行比较。预计这项研究将为最终设计一种接近原子分辨率的自旋敏感隧道显微镜提供信息。

This project will combine spin-polarized tunneling methods with some of the techniques of scanning tunneling microscopy (STM) in an ultra high vacuum environment. The techniques will be applied to probe the surface magnetism of superconducting and magnetic materials. The research will include low temperature studies of spin-orbit and magnetic scattering in superconductors, magnetic impurities in normal metals, and tunneling measurements with oriented single-crystal ferromagnets. Part of the project will involve continued development of superconducting and ferromagnetic tips crucial to operation of STM and spin polarized tunneling SSTM apparatus. Ferromagnetic to ferromagnetic tunneling measurements will be made at temperatures up to 300 K with various materials and modulation techniques. The STM techniques will initially be used to position the tunneling tip at a proper site within tunneling distance. Later the limits of spatial resolution will be investigated in the study of individual impurities or antiferromagnets. These results will be compared with theory. It is expected that this study will give information leading to eventual design of a spin-sensitive tunneling microscope with close to atomic resolution.