Thermally activated reversal in exchange-coupled structures

Y. G. Wang; A. K. Petford-Long; H. Laidler; K. O'Grady; M. T. Kief

doi:10.1109/TMAG.2002.803158

Thermally activated reversal in exchange-coupled structures

Y. G. Wang^*, A. K. Petford-Long, H. Laidler, K. O'Grady, M. T. Kief

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Conference article › peer-review

1 Scopus citations

Abstract

In this paper, we study the thermally activated reversal of IrMn/CoFe exchange-coupled structures using Lorentz microscopy and magnetometry. An asymmetry and a training effect were found on the hysteresis loops both with and without holding the film at negative saturation of the ferromagnetic layer. Holding the film at negative saturation results in the hysteresis loop shifting toward zero field. We believe that, in this system, two energy barrier distributions with different time constants coexist. The large-time-constant thermally activated reversal of the antiferromagnetic layer contributes to a increasing shift of the entire hysteresis loop toward zero field with increased period of time spent at negative saturation of the ferromagnetic layer. The small-time-constant thermal activation contributes to asymmetry in the magnetization reversal and training effects.

Original language	English (US)
Pages (from-to)	2773-2775
Number of pages	3
Journal	IEEE Transactions on Magnetics
Volume	38
Issue number	5 I
DOIs	https://doi.org/10.1109/TMAG.2002.803158
State	Published - Sep 2002
Event	2002 International Magnetics Conference (Intermag 2002) - Amsterdam, Netherlands Duration: Apr 28 2002 → May 2 2002

Keywords

Exchange-coupling
IrMn/CoFe
Magnetization reversal
Thermal activation

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

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title = "Thermally activated reversal in exchange-coupled structures",

abstract = "In this paper, we study the thermally activated reversal of IrMn/CoFe exchange-coupled structures using Lorentz microscopy and magnetometry. An asymmetry and a training effect were found on the hysteresis loops both with and without holding the film at negative saturation of the ferromagnetic layer. Holding the film at negative saturation results in the hysteresis loop shifting toward zero field. We believe that, in this system, two energy barrier distributions with different time constants coexist. The large-time-constant thermally activated reversal of the antiferromagnetic layer contributes to a increasing shift of the entire hysteresis loop toward zero field with increased period of time spent at negative saturation of the ferromagnetic layer. The small-time-constant thermal activation contributes to asymmetry in the magnetization reversal and training effects.",

keywords = "Exchange-coupling, IrMn/CoFe, Magnetization reversal, Thermal activation",

author = "Wang, {Y. G.} and Petford-Long, {A. K.} and H. Laidler and K. O'Grady and Kief, {M. T.}",

note = "Funding Information: Manuscript received February 11, 2002; revised May 22, 2002. This work was supported by EPSRC and Seagate Technology. Y. G. Wang and A. K. Petford-Long are with the Department of Materials, University of Oxford, Oxford OX1 3PH, U.K. H. Laidler and K. O{\textquoteright}Grady are with the Department of Physics, University of York, York YO10 5DD, U.K. M. T. Kief is with Seagate Technology, 7801 Computer Avenue South, Minneapolis, MN 55435-5489 USA. Digital Object Identifier 10.1109/TMAG.2002.803158.; 2002 International Magnetics Conference (Intermag 2002) ; Conference date: 28-04-2002 Through 02-05-2002",

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language = "English (US)",

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journal = "IEEE Transactions on Magnetics",

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publisher = "Institute of Electrical and Electronics Engineers Inc.",

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AU - Wang, Y. G.

AU - Petford-Long, A. K.

AU - Laidler, H.

AU - O'Grady, K.

AU - Kief, M. T.

N1 - Funding Information: Manuscript received February 11, 2002; revised May 22, 2002. This work was supported by EPSRC and Seagate Technology. Y. G. Wang and A. K. Petford-Long are with the Department of Materials, University of Oxford, Oxford OX1 3PH, U.K. H. Laidler and K. O’Grady are with the Department of Physics, University of York, York YO10 5DD, U.K. M. T. Kief is with Seagate Technology, 7801 Computer Avenue South, Minneapolis, MN 55435-5489 USA. Digital Object Identifier 10.1109/TMAG.2002.803158.

PY - 2002/9

Y1 - 2002/9

N2 - In this paper, we study the thermally activated reversal of IrMn/CoFe exchange-coupled structures using Lorentz microscopy and magnetometry. An asymmetry and a training effect were found on the hysteresis loops both with and without holding the film at negative saturation of the ferromagnetic layer. Holding the film at negative saturation results in the hysteresis loop shifting toward zero field. We believe that, in this system, two energy barrier distributions with different time constants coexist. The large-time-constant thermally activated reversal of the antiferromagnetic layer contributes to a increasing shift of the entire hysteresis loop toward zero field with increased period of time spent at negative saturation of the ferromagnetic layer. The small-time-constant thermal activation contributes to asymmetry in the magnetization reversal and training effects.

AB - In this paper, we study the thermally activated reversal of IrMn/CoFe exchange-coupled structures using Lorentz microscopy and magnetometry. An asymmetry and a training effect were found on the hysteresis loops both with and without holding the film at negative saturation of the ferromagnetic layer. Holding the film at negative saturation results in the hysteresis loop shifting toward zero field. We believe that, in this system, two energy barrier distributions with different time constants coexist. The large-time-constant thermally activated reversal of the antiferromagnetic layer contributes to a increasing shift of the entire hysteresis loop toward zero field with increased period of time spent at negative saturation of the ferromagnetic layer. The small-time-constant thermal activation contributes to asymmetry in the magnetization reversal and training effects.

KW - Exchange-coupling

KW - IrMn/CoFe

KW - Magnetization reversal

KW - Thermal activation

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JO - IEEE Transactions on Magnetics

JF - IEEE Transactions on Magnetics

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T2 - 2002 International Magnetics Conference (Intermag 2002)

Y2 - 28 April 2002 through 2 May 2002

ER -

Thermally activated reversal in exchange-coupled structures

Abstract

Keywords

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