Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.

Bibliographic Details
Main Author: Finley, Joseph T. (Joseph Tyler)
Other Authors: Marc A. Baldo.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2017
Subjects:
Online Access:http://hdl.handle.net/1721.1/111913
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author Finley, Joseph T. (Joseph Tyler)
author2 Marc A. Baldo.
author_facet Marc A. Baldo.
Finley, Joseph T. (Joseph Tyler)
author_sort Finley, Joseph T. (Joseph Tyler)
collection MIT
description Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.
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spelling mit-1721.1/1119132019-04-10T09:07:13Z Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys Finley, Joseph T. (Joseph Tyler) Marc A. Baldo. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science. Electrical Engineering and Computer Science. Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017. Cataloged from PDF version of thesis. Includes bibliographical references (pages 51-54). Spintronic devices promise to be an energy efficient alternative to complementary metal oxide semiconductor devices for logic and memory. However, in order to be more competitive, further reductions in switching energy and switching speed are needed. Recently, there has been interest in using antiferromagnetically coupled materials instead of ferromagnetic materials to store information. Compared with ferromagnetic materials, antiferromagnetically coupled systems exhibit faster dynamics and are more stable against external magnetic field perturbations, which could potentially enable spintronic devices with higher speed and density. Despite the potential advantages of information storage in antiferromagnetically coupled materials, it remains uncertain whether one can efficiently control the magnetic state because of the cancelled net magnetic moment. This thesis reports spin-orbit torque induced magnetization switching of ferrimagnetic Co₁-xTbx thin films with perpendicular magnetic anisotropy. By varying the relative concentrations of the two atomic species, one can reach compensation points where the net magnetic moment or angular momentum goes to zero. We demonstrate current induced switching in all of the studied film compositions, including those near the magnetization compensation point. We then quantify the spin-orbit torque induced effective field, where we find that close to the compensation point, there is a divergent behavior that scales with the inverse of the magnetization, consistent with angular momentum conservation. The large effective spin-orbit torque, previously demonstrated fast dynamics, and small net magnetization in these ferrimagnetic systems promise spintronic devices that are faster and more scalable than traditional ferromagnetic systems. by Joseph T. Finley. S.M. 2017-10-18T15:09:46Z 2017-10-18T15:09:46Z 2017 2017 Thesis http://hdl.handle.net/1721.1/111913 1005261005 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 54 pages application/pdf Massachusetts Institute of Technology
spellingShingle Electrical Engineering and Computer Science.
Finley, Joseph T. (Joseph Tyler)
Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title_full Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title_fullStr Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title_full_unstemmed Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title_short Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
title_sort spin orbit torque switching of compensated ferrimagnetic cobalt terbium alloys
topic Electrical Engineering and Computer Science.
url http://hdl.handle.net/1721.1/111913
work_keys_str_mv AT finleyjosephtjosephtyler spinorbittorqueswitchingofcompensatedferrimagneticcobaltterbiumalloys