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Precessional strategies for the ultrafast switching of soft and hard magnetic nanostructures

Published online by Cambridge University Press:  10 February 2011

T. Devolder ,
M. Belmeguenai ,
H. W. Schumacher ,
C. Chappert  and
Y. Suzuki
T. Devolder
Affiliation:
Institut d'Electronique Fondamentale, UMR CNRS 8622, Université Paris-Sud, 91405 Orsay, FRANCE.
M. Belmeguenai
Affiliation:
Institut d'Electronique Fondamentale, UMR CNRS 8622, Université Paris-Sud, 91405 Orsay, FRANCE.
H. W. Schumacher
Affiliation:
Institut d'Electronique Fondamentale, UMR CNRS 8622, Université Paris-Sud, 91405 Orsay, FRANCE.
C. Chappert
Affiliation:
Institut d'Electronique Fondamentale, UMR CNRS 8622, Université Paris-Sud, 91405 Orsay, FRANCE.
Y. Suzuki
Affiliation:
Institut d'Electronique Fondamentale, UMR CNRS 8622, Université Paris-Sud, 91405 Orsay, FRANCE.
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Abstract

We discuss the precessional, quasi-ballistic switching of magnetization in magnetic nanostructures. In soft spin-valve cells, fast and energy-cost effective magnetization switching can be triggered by a transverse field pulse of moderate amplitude, below the in plane anisotropy field, because of an amplification effect brought by the demagnetizing field at the early stage of the reversal. The same effect is no more possible in hard nanomagnets with perpendicular easy magnetization axis. We propose a new type of nanostructured magnetic device, designed to overcome this limitation. The speed is obtained through the use of a very high effective magnetic field, obtained by incorporating a significant exchange field which stores the energy in the form of a constrained domain wall surrounding a region of high magnetic anisotropy. This stored energy is partially available to accelerate the magnetization reversal in a precessional scenario. We illustrate the concept by studying numerically a model system. The key parameter for the reversal is the ratio of the domain wall width to the structure lateral dimension. Possible routes for device preparation are discussed. Promising application to magnetic storage are anticipated.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 746: Symposia Q/R – Magnetoelectronics-Novel Magnetic Phenomena in Nanostructures – Advanced Characterization of Artificially Structured Magnetic Materials , 2002 , Q8.4
Copyright
Copyright © Materials Research Society 2003

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References

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