Spin supercurrents in ferromagnetic and antiferromagnetic films

铁磁和反铁磁薄膜中的自旋超电流

• 批准号: 1610146
• 负责人: Ilya Krivorotov
• 金额: $ 42万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1610146&HistoricalAwards=false
• 关键词: Spin; supercurrents; ferromagnetic; antiferromagnetic; films

Nontechnical abstract:Electric currents in electronic devices such as cell phones and computers typically lose a large fraction of their power supply's energy to the device heating. However, electric currents in some materials can flow without generating heat if the material's temperature is low enough. Such materials called superconductors are used, for example, in magnetic resonance imaging scanners to create large magnetic fields. The aim of this research project is to discover a magnetic analog of superconductivity, which is called spin superfluidity, and to study its stability at room temperature. Spin superfluids can transport magnetic currents with minimal losses similar to electric currents in superconductors. The nearly lossless magnetic currents may find use in the next generation of computers that employ magnetic materials for information storage and processing. The principal investigator and the graduate students involved in this research develop hands-on demonstrations on magnetism and superconductivity for middle school students that stimulate the students' interest in science and engineering. Technical abstractThe main goal of the proposed research is to experimentally realize a new state of magnetic matter called spin superfluid, which has been predicted to exist in ferromagnets and antiferromagnets with easy plane magnetic anisotropy. The name "spin superfluid" stems from the similarity of its properties to those of superfluid liquid helium and Cooper pair condensate in superconductors. In particular, the spin superfluid is expected to support spin supercurrents that transport spin angular momentum over distances orders of magnitude longer than those achievable with spin waves. The goal of this project is to induce the spin superfluid state in thin films and nanowires of ferromagnets and antiferromagnet via injection of pure spin currents polarized perpendicular to the easy plane of magnetic anisotropy. The spin superfluid state can be detected electrically via a unique low-frequency supercurrent mode predicted to propagate over microscopic distances in easy-plane magnetic materials. The scope of work also includes studies of a chiral spin superfluid state induced by Dzyaloshinskii-Moriya interaction in ferromagnetic nanowires. Stability of the spin superfluid state against thermally induced magnetic vortex formation is investigated both experimentally and via large-scale micromagnetic simulations.

非技术摘要：电子设备（如手机和电脑）中的电流通常会将其电源的大部分能量损失到设备加热中。然而，如果材料的温度足够低，某些材料中的电流可以流动而不产生热量。这种被称为超导体的材料被用于例如磁共振成像扫描仪中以产生大磁场。该研究项目的目的是发现超导性的磁性类似物，称为自旋超流性，并研究其在室温下的稳定性。自旋超流体可以以最小的损耗传输磁流，类似于超导体中的电流。这种几乎无损的磁流可能会在下一代计算机中找到用途，这些计算机采用磁性材料进行信息存储和处理。主要研究者和参与这项研究的研究生为中学生开发了关于磁性和超导性的实践演示，激发了学生对科学和工程的兴趣。 技术摘要所提出的研究的主要目标是在实验上实现一种称为自旋超流体的磁性物质的新状态，该状态已被预测存在于具有易平面磁各向异性的铁磁体和反铁磁体中。“自旋超流体”这个名字源于它的性质与超导体中的超流液氦和库珀对凝聚体的性质相似。特别是，自旋超流体预计将支持自旋超流，其传输自旋角动量的距离比自旋波可实现的距离长几个数量级。本项目的目标是通过注入垂直于磁各向异性的易磁化面极化的纯自旋电流，在铁磁体和反铁磁体的薄膜和纳米线中诱导自旋超流态。自旋超流状态可以通过一种独特的低频超流模式进行电检测，该模式预计将在易平面磁性材料中传播超过微观距离。工作范围还包括在铁磁纳米线中由Dzyaloshinskiii-Moriya相互作用诱导的手性自旋超流态的研究。通过实验和大尺度微磁学模拟研究了自旋超流态对热致磁涡旋形成的稳定性。

项目成果

Measurement of Microwave Signal Frequency by a Pair of Spin-Torque Microwave Diodes

• DOI: 10.1109/lmag.2021.3088400
• 发表时间: 2021-06
• 期刊: IEEE Magnetics Letters
• 影响因子: 1.2
• 作者: P. Artemchuk;Jieyi Zhang;O. Prokopenko;E. Bankowski;T. Meitzler;I. Krivorotov;J. Katine;V. Tyberkevych;A. Slavin

Dimensional crossover in spin Hall oscillators

• DOI: 10.1103/physrevb.102.054422
• 发表时间: 2020-05
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Andrew Smith;K. Sobotkiewich;Amanatullah Khan;E. Montoya;Liu Yang;Zheng Duan;T. Schneider;K. Lenz;J. Lindner;Kyongmo An;Xiaoqin Li;I. Krivorotov

Immunity of nanoscale magnetic tunnel junctions with perpendicular magnetic anisotropy to ionizing radiation

• DOI: 10.1038/s41598-020-67257-2
• 发表时间: 2020-06-23
• 期刊: SCIENTIFIC REPORTS
• 影响因子: 4.6
• 作者: Montoya, Eric Arturo;Chen, Jen-Ru;Krivorotov, Ilya N.
• 通讯作者: Krivorotov, Ilya N.

Parametric Resonance of Magnetization Excited by Electric Field

• DOI: 10.1021/acs.nanolett.6b04725
• 发表时间: 2017-01-01
• 期刊: NANO LETTERS
• 影响因子: 10.8
• 作者: Chen, Yu-Jin;Lee, Han Kyu;Krivorotov, Ilya N.
• 通讯作者: Krivorotov, Ilya N.