Exquisitely balanced thermal sensitivity of the stochastic switching process in macroscopic ferromagnetic ring elements -: art. no. 184430

被引:29
作者
Hayward, TJ [1 ]
Moore, TA
Tse, DHY
Bland, JAC
Castaño, FJ
Ross, CA
机构
[1] Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England
[2] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA
关键词
D O I
10.1103/PhysRevB.72.184430
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We have studied the repeatability of the magnetic switching behavior of macroscopic ferromagnetic permalloy ring elements using focused magneto-optic Kerr effect magnetometry. In 5 mu m diameter permalloy rings, the circulation of the stable vortex state is found to alternate stochastically from one applied field cycle to the next due to the influence of thermal fluctuations. Micromagnetic simulations are used to demonstrate that the symmetry of the structure creates an exquisitely balanced system where the configuration of a nanoscopic region of magnetic moments dictates the switching mechanism of the entire macroscopic structure, resulting in a degree of sensitivity to thermal agitation usually only observed in structures three orders of magnitude smaller.
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页数:6
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