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Current-induced two-level fluctuations in pseudo-spin-valve (Co/Cu/Co) nanostructures
A Fábián1, C Terrier, S Serrano Guisan
1Institut de Physique des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
Physical Review Letters
|February 3, 2004
Summary
Spin-polarized currents induce magnetization switching in pseudo-spin-valve nanowires at room temperature. This current effectively acts as a bias field, reducing switching times to microseconds.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Pseudo-spin-valve pillars are crucial for spintronic devices.
- Controlling magnetization dynamics in nanoscale structures is essential for data storage applications.
- Understanding current-induced effects in magnetic nanowires is key to advancing magnetic random-access memory (MRAM) technologies.
Purpose of the Study:
- To investigate the two-level fluctuations of magnetization states in Co/Cu/Co pseudo-spin-valve pillars.
- To analyze the statistical properties of residence times in parallel and antiparallel magnetization states under spin-polarized currents.
- To determine the influence of current intensity and polarity on magnetization dynamics and switching behavior.
Main Methods:
- Fabrication of electrodeposited Co/Cu/Co pseudo-spin-valve nanowires (approx. 40 nm diameter, 6000 nm length).
- Application of spin-polarized currents (10^7 A/cm^2) at room temperature.
- Statistical analysis of residence times in different magnetization states.
Main Results:
- Two-level magnetization fluctuations were triggered by spin-polarized currents.
- Current intensity showed a distinct dependence on the statistical properties of residence times.
- The applied current acted as a bias field, equalizing residence times and reducing switching to the microsecond range.
- This effect was independent of current polarity and suggested an effective temperature for magnetization.
Conclusions:
- Spin-polarized currents can effectively control magnetization switching in pseudo-spin-valve nanowires.
- The current-induced bias field offers a novel mechanism for manipulating magnetic states.
- The observed microsecond switching times are promising for high-speed spintronic device applications.
- The concept of an effective temperature provides a new perspective on current-induced magnetization dynamics.
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