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

缺氧 EuO(1-x) 中磁斯格明子和磁极化子的研究

• 批准号: 1710512
• 负责人: Jinke Tang
• 金额: $ 59.54万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710512&HistoricalAwards=false
• 关键词: Investigation; Magnetic; Skyrmions; Polarons; Oxygen

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).

摘要：本项目研究了一种独特的磁性半导体-缺氧氧化铕EuO（1-x）中的新磁态。在EuO（1-x）中发现的这些新型磁态作为具有拓扑保护稳定性和最小能量耗散的下一代小型磁存储器具有很好的应用前景。揭示和理解原子尺度以及这些磁性状态的宏观特征，将推动科学在一个重要的技术领域的发展。这里所追求的物理学也为氧空位的作用提供了重要的见解，因为氧空位工程正成为使用各种氧化物材料实现实用器件的一种有吸引力的方法。该项目为凝聚态物质和材料物理学的学生提供了独特的研究和教育经验，并在协作学习环境中培养学生。学生们参观怀俄明州的高中，并与高中教师合作，将新的研究知识整合到当前的标准科学课程中。技术摘要：有不可否认的迹象表明，在缺氧的EuO（1-x）中可能存在磁性微粒。假设在69k以上观测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t69k时，磁极化子转变为磁天子（铁磁宿主中的非平凡自旋织构）。本项目的目标是采用几种新方法来探索潜在的skyrmion形成并研究其形成机制。这是通过材料合成和氧空位控制的结合来实现的，随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，实验研究还得到了计算研究的辅助。具体方法有三种：1)探测磁极化子和磁天子，确定它们与氧空位的关系；2)在第一居里温度（69 K）下测试磁激子和极化子的形成机制；3)建立EuO（1-x）的磁相图。

项目成果

Molecular tunneling in large tubes of 3D nitrogenated micropore materials

• DOI: 10.1063/1.5045194
• 发表时间: 2018-11
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: A. Pimachev;Y. Dahnovsky

Metal-insulator transition temperature in EuO1−x films as a function of exposure time in air

EuO1-x 薄膜中的金属-绝缘体转变温度与空气中暴露时间的函数关系

• DOI: 10.1016/j.jmmm.2021.168964
• 发表时间: 2022
• 期刊: Journal of Magnetism and Magnetic Materials
• 影响因子: 2.7
• 作者: Shrestha, Narendra;Tang, Jinke
• 通讯作者: Tang, Jinke

Converting raw coal powder into polycrystalline nano-graphite by metal-assisted microwave treatment

• DOI: 10.1016/j.nanoso.2020.100660
• 发表时间: 2021-02
• 期刊: Nano-Structures and Nano-Objects
• 作者: Christoffer A. Masi;Teneil A. Schumacher;J. Hilman;Rabindra Dulal;Gaurab Rimal;Bang Xu;Brian M. Leonard;Jinke Tang;M. Fan;T. Chien

Threshold behaviors of direct and Hall currents in topological spin-Hall effect

拓扑自旋霍尔效应中直流电流和霍尔电流的阈值行为

• DOI: 10.1016/j.jmmm.2021.168492
• 发表时间: 2022
• 期刊: Journal of Magnetism and Magnetic Materials
• 影响因子: 2.7
• 作者: Zadorozhnyi, Andrei;Dahnovsky, Yuri
• 通讯作者: Dahnovsky, Yuri

Perspectives of cross-sectional scanning tunneling microscopy and spectroscopy for complex oxide physics

复合氧化物物理的横截面扫描隧道显微镜和光谱学的前景

• DOI: 10.1016/j.physleta.2018.01.016
• 发表时间: 2018
• 期刊: Physics Letters A
• 影响因子: 2.6
• 作者: Wang, Aaron;Chien, TeYu
• 通讯作者: Chien, TeYu