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Switchable hardening of a ferromagnet at fixed temperature

Silevitch, D. M. and Aeppli, G. and Rosenbaum, T. F. (2010) Switchable hardening of a ferromagnet at fixed temperature. Proceedings of the National Academy of Sciences of the United States of America, 107 (7). pp. 2797-2800. ISSN 0027-8424. PMCID PMC2840359. doi:10.1073/pnas.0910575107.

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The intended use of a magnetic material, from information storage to power conversion, depends crucially on its domain structure, traditionally crafted during materials synthesis. By contrast, we show that an external magnetic field, applied transverse to the preferred magnetization of a model disordered uniaxial ferromagnet, is an isothermal regulator of domain pinning. At elevated temperatures, near the transition into the paramagnet, modest transverse fields increase the pinning, stabilize the domain structure, and harden the magnet, until a point where the field induces quantum tunneling of the domain walls and softens the magnet. At low temperatures, tunneling completely dominates the domain dynamics and provides an interpretation of the quantum phase transition in highly disordered magnets as a localization/delocalization transition for domain walls. While the energy scales of the rare earth ferromagnet studied here restrict the effects to cryogenic temperatures, the principles discovered are general and should be applicable to existing classes of highly anisotropic ferromagnets with ordering at room temperature or above.

Item Type:Article
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URLURL TypeDescription CentralArticle
Silevitch, D. M.0000-0002-6347-3513
Additional Information:Copyright © 2010 National Academy of Sciences. Edited by Sidney Nagel, University of Chicago, and approved December 14, 2009 (received for review September 16, 2009). Published ahead of print January 29, 2010. The work at the University of Chicago was supported by DOE Basic Energy Sciences under Grant No. DEFG02-99ER45789, while work in London was supported via the United Kingdom Engineering and Physical Sciences Research Council. D.M.S. acknowledges use of the central facilities of the NSF Materials Research Science & Engineering Center. Author contributions: D.M.S., G.A., and T.F.R. designed research; D.M.S. and T.F.R. performed research; D.M.S. analyzed data; and D.M.S., G.A., and T.F.R. wrote the paper. The authors declare no conflict of interest. This Direct Submission article had a prearranged editor.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-99ER45789
Engineering and Physical Sciences Research Council (EPSRC)UNSPECIFIED
Subject Keywords:domain reversal; ferromagnetism; magnetic storage; quantum tunneling; random fields
Issue or Number:7
PubMed Central ID:PMC2840359
Record Number:CaltechAUTHORS:20140707-163025699
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Official Citation:D. M. Silevitch, G. Aeppli, and T. F. Rosenbaum Switchable hardening of a ferromagnet at fixed temperature PNAS 2010 107 (7) 2797-2800; published ahead of print January 29, 2010, doi:10.1073/pnas.0910575107
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46931
Deposited By: George Porter
Deposited On:09 Jul 2014 15:01
Last Modified:10 Nov 2021 17:31

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