Long-timescale fluctuations in zero-field magnetic vortex oscillations driven by dc spin-polarized current

被引：35

作者：

Pribiag, V. S. ^{[1
]}

Finocchio, G. ^{[2
]}

Williams, B. J. ^{[3
]}

Ralph, D. C. ^{[1
]}

Buhrman, R. A. ^{[1
]}

机构：

[1] Cornell Univ, Ithaca, NY 14853 USA

[2] Univ Messina, Dipartimento Fis Mat & Ingn Elettron, I-98166 Messina, Italy

[3] Univ Texas Dallas, Dallas, TX 75080 USA

来源：

PHYSICAL REVIEW B | 2009年 / 80卷 / 18期

关键词：

fine structure; magnetic domains; magnetic switching; spin fluctuations; spin polarised transport; MICROWAVE GENERATION; TRANSFER TORQUE; EXCITATIONS;

D O I：

10.1103/PhysRevB.80.180411

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report time and frequency domain studies of spin-torque-driven vortex self-oscillations at zero magnetic field. We observe two types of abrupt fluctuations in the frequency and amplitude, with very long random mean lifetimes (similar to 10(2) to similar to 10(4) oscillation cycles). First, we observe fluctuations between two center frequencies separated by 10s of MHz that we identify with switching between quasiuniform and vortex states of the magnetic polarizing layer. Second, we resolve much smaller, discrete frequency fluctuations that lead to a fine structure of the oscillations. We find that this fine structure plays a key role in determining the long-time average linewidths and we suggest a possible physical origin.

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页数：4

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