Investigation of Magnetic Skyrmions and Magnetic Polarons in Oxygen Deficient EuO(1-x)

非技术摘要：本项目研究了一种独特的磁性半导体--氧缺乏型EuO(1-x)中的新磁态。在EuO(1-x)中发现的这些新的磁态具有拓扑保护的稳定性和最小的能量耗散，在下一代小型磁存储器中具有很好的应用前景。揭示和理解这些磁态的原子尺度和宏观特征，促进了科学在一个具有技术重要性的领域的发展。这里所追求的物理学也提供了对氧空位作用的重要洞察，因为氧空位工程正在成为实现使用各种类型的氧化物材料的实际器件的一种有吸引力的方式。该项目为学生提供独特的凝聚态和材料物理研究和教育体验，并在协作学习环境中培训学生。学生们参观怀俄明州的高中，并与高中教师合作，将新的研究知识融入当前的标准科学课程。技术摘要：不可否认的迹象表明，磁性天子可能存在于缺氧的EuO(1-x)中。假设在69K以上观察到的磁有序是由于磁极化子(顺磁环境中的磁有序)的形成，当T为69K时，磁极化子转变为磁性天米子(铁磁主体中的非平凡的自旋织构)。本项目的目标是采用几种新的方法来探测潜在的天米子的形成并研究其形成机制。这是通过材料合成和氧空位控制相结合的方式实现的，然后通过自旋极化扫描隧道显微镜进行直接观察，并通过旨在检测拓扑霍尔效应的输运测量进行表征。此外，实验研究还辅之以计算研究。采用了三种具体的方法：1)探测磁极化子和天子并确定它们与氧空位的相关性；2)测试第一居里温度(69K)上的磁天子和极化子的形成机制；3)建立EuO(1-x)的磁相图。

Non-Technical Abstract:This project investigates novel magnetic states in a unique magnetic semiconductor - oxygen deficient europium monoxide EuO(1-x). These novel magnetic states found in EuO(1-x) have promising applications as next generation small magnetic memories with topologically protected stability and minimal energy dissipation. Revealing and understanding the atomic-scale as well as macroscopic features of these magnetic states advance the sciences in an area of technological importance. The physics pursued here also provides significant insight into the roles of the oxygen vacancies as oxygen vacancy engineering is becoming an attractive way to realize practical devices using various types of oxide materials. The project offers unique research and educational experiences for students in condensed matter and materials physics and trains students in a collaborative learning environment. Students visit high schools in Wyoming and partner with high school teachers to integrate new knowledge of research into the current standard science curriculum. Technical Abstract:There are undeniable signs that suggest magnetic skyrmions may exist in oxygen deficient EuO(1-x). It is hypothesized that the observed magnetic ordering above 69 K is due to the formation of magnetic polarons (magnetic ordering in a paramagnetic environment), which transitions to magnetic skyrmions (nontrivial spin texture in a ferromagnetic host) when T 69 K. The goal of this project is to take several novel approaches to probe the potential skyrmion formation and investigate the mechanisms for their formation. This is achieved by a combination of material synthesis and oxygen vacancy control followed by direct observation via spin-polarized scanning tunneling microscopy and characterization with transport measurements that aim to detect topological Hall effect. In addition, the experimental studies are aided by computational investigations. Three specific approaches are taken: 1) probing magnetic polarons and skyrmions and determining their correlation with the oxygen vacancies; 2) testing magnetic skyrmion and polaron formation mechanisms across the first Curie temperature (69 K); and 3) establishing the magnetic phase diagram for EuO(1-x).