Acquisition of a Custom Molecular Beam Epitaxy System for Metals and Insulators

小行星9625892 近年来，金属铁磁体中的巨磁电阻（GMR）、交换各向异性（EA）和垂直各向异性在技术上的潜在应用极大地推动了人们对磁性薄膜和超晶格的兴趣。 然而，该领域的许多感兴趣的主题尚未得到充分探索，包括由交替的金属和绝缘层组成的超晶格中的磁相互作用，以及纯绝缘磁性超晶格。 这些类型的超晶格可以进一步加深我们对磁相互作用的基本理解，并导致意想不到的技术。 该奖项赞助的分子束外延（MBE）系统旨在生长和表征各种磁性超晶格，包括仅由绝缘体，仅由金属或绝缘体和金属组合组成的磁性超晶格。 %表征这些材料的结构是很重要的，因为磁性薄膜和超晶格的表面和界面结构会显著影响它们的物理性能。 为了理解这些特性，研究这些材料的表面作为生长参数的函数是至关重要的，例如膜厚度、生长温度和生长速率。 结构研究还可以帮助区分结构效应与本征超晶格和界面效应。 这可以使用表面敏感技术如反射高能电子衍射（RHEED）、低能电子衍射（LEED）、扫描隧道显微镜（STM）和X射线光电子能谱（XPS）原位完成，而不受空气污染。 这一信息将补充非原位X射线衍射测量。 ***

9625892 Lederman The considerable recent interest in magnetic thin films and superlattices has been fueled in large part by the potential technological applications of giant magnetoresistance (GMR), exchange anisotropy (EA), and perpendicular anisotropies in metallic ferromagnets. However, numerous topics of interest in this field have not been fully explored, including the magnetic interactions in superlattices composed of alternating metallic and insulating layers, and purely insulating magnetic superlattices. These types of superlattices could further our basic understanding of magnetic interactions and lead to unexpected technologies. The molecular beam epitaxy (MBE) system sponsored by this award is designed to grow and characterize a wide variety of magnetic superlattices, including those composed only of insulators, only of metals, or combinations of insulators and metals. %%% Characterizing the structure of these materials is important because the surface and interface structure in magnetic thin films and superlattices can significantly affect their physical properties. In order to understand these properties, it is crucial to study the surface of these materials as a function of growth parameters, such as film thickness, growth temperature, and growth rate. Structural studies can also aid in distinguishing the structural effects from the intrinsic superlattice and interface effects. This can be done in-situ using surface-sensitive techniques such as reflection high energy electron diffraction (RHEED), low energy electron diffraction (LEED), scanning tunneling microscopy (STM), and x-ray photoelectron spectroscopy (XPS) without contamination from the air. This information will be complemented with ex-situ x-ray diffraction measurements. ***