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Title: Nanoscale imaging of magnetization reversal driven by spin-orbit torque

Abstract

We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, either Pt or Ta, upon which the CoFeB rectangles are deposited. We image the CoFeB magnetization before and after a current pulse to see the effect of spin-orbit torque on the magnetic nanostructure. The observed changes in magnetic structure can be complex, deviating significantly from a simple macrospin approximation, especially in larger elements. Overall, however, the directions of the magnetization reversal in the Pt and Ta devices are opposite, consistent with the opposite signs of the spin Hall angles of these materials. Lastly, our results elucidate the effects of current density, geometry, and magnetic domain structure on magnetization switching driven by spin-orbit torque.

Authors:
 [1];  [1];  [1];  [2];  [1];  [1];  [1]
  1. National Institute of Standards and Technology, Gaithersburg, MD (United States)
  2. National Institute of Standards and Technology, Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1352370
Report Number(s):
LA-UR-16-27440
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1701616
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 9; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; material science; spin-orbit torque; spin Hall effect; CoFeB

Citation Formats

Gilbert, Ian, Chen, P. J., Gopman, Daniel B., Balk, Andrew L., Pierce, Daniel T., Stiles, Mark D., and Unguris, John. Nanoscale imaging of magnetization reversal driven by spin-orbit torque. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.94.094429.
Gilbert, Ian, Chen, P. J., Gopman, Daniel B., Balk, Andrew L., Pierce, Daniel T., Stiles, Mark D., & Unguris, John. Nanoscale imaging of magnetization reversal driven by spin-orbit torque. United States. doi:10.1103/PhysRevB.94.094429.
Gilbert, Ian, Chen, P. J., Gopman, Daniel B., Balk, Andrew L., Pierce, Daniel T., Stiles, Mark D., and Unguris, John. 2016. "Nanoscale imaging of magnetization reversal driven by spin-orbit torque". United States. doi:10.1103/PhysRevB.94.094429. https://www.osti.gov/servlets/purl/1352370.
@article{osti_1352370,
title = {Nanoscale imaging of magnetization reversal driven by spin-orbit torque},
author = {Gilbert, Ian and Chen, P. J. and Gopman, Daniel B. and Balk, Andrew L. and Pierce, Daniel T. and Stiles, Mark D. and Unguris, John},
abstractNote = {We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, either Pt or Ta, upon which the CoFeB rectangles are deposited. We image the CoFeB magnetization before and after a current pulse to see the effect of spin-orbit torque on the magnetic nanostructure. The observed changes in magnetic structure can be complex, deviating significantly from a simple macrospin approximation, especially in larger elements. Overall, however, the directions of the magnetization reversal in the Pt and Ta devices are opposite, consistent with the opposite signs of the spin Hall angles of these materials. Lastly, our results elucidate the effects of current density, geometry, and magnetic domain structure on magnetization switching driven by spin-orbit torque.},
doi = {10.1103/PhysRevB.94.094429},
journal = {Physical Review B},
number = 9,
volume = 94,
place = {United States},
year = 2016,
month = 9
}

Journal Article:
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