Related Experiment Video
Updated: May 28, 2026
06:53
Scanning SQUID Study of Vortex Manipulation by Local Contact
Published on: February 1, 2017
Control of magnetic fluctuations by spin current
V E Demidov1, S Urazhdin, E R J Edwards
1Institute for Applied Physics and Center for Nonlinear Science, University of Muenster, Corrensstrasse 2-4, 48149 Muenster, Germany. demidov@uni-muenster.de
Physical Review Letters
|October 11, 2011
Summary
Spin current injection controls magnetic fluctuations in Permalloy microdisks. Electric current direction and nonlinear magnon interactions influence these effects, offering potential for reducing thermal noise in spintronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spintronics
Background:
- Spin current injection is a key mechanism in spintronics.
- Understanding the interplay between spin currents and magnetic fluctuations is crucial for device performance.
- Permalloy microdisks are common elements in spintronic devices.
Purpose of the Study:
- To investigate the interaction between spin current and magnetic fluctuations in a Permalloy microdisk.
- To determine the influence of electric current direction on magnetic fluctuations.
- To explore the role of nonlinear magnon-magnon interactions in this system.
Main Methods:
- Microfocus Brillouin light scattering spectroscopy was employed.
- Experiments were conducted on a Permalloy microdisk situated on a platinum strip.
- An electric current was passed through the platinum strip to generate spin current.
Main Results:
- Magnetic fluctuations in the microdisk were found to be suppressed or enhanced by varying the electric current direction.
- Nonlinear magnon-magnon interactions were identified as a significant factor influencing the spin current's effect on magnetic fluctuations.
- The study demonstrated controllable manipulation of magnetic fluctuations.
Conclusions:
- Spin current injection provides an effective means to control magnetic fluctuations in Permalloy microdisks.
- The findings highlight the importance of considering nonlinear magnon dynamics in spintronic device design.
- This research offers a pathway for the controllable reduction of thermal noise in spintronic nanodevices.
Related Concept Videos
01:27Magnetic Fields
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:25Magnetic Force On A Current-Carrying Conductor
Moving charges experience a force in a magnetic field. Since the magnetic fields produced by moving charges are proportional to the current, a conductor carrying a current creates a magnetic field around it.
Consider a compass placed near a current-carrying wire. The wire experiences a force that aligns the needle of the compass tangentially around the wire. Thus, the current-carrying wire produces concentric circular loops of magnetic field. The magnetic field generated by a wire can be...
Consider a compass placed near a current-carrying wire. The wire experiences a force that aligns the needle of the compass tangentially around the wire. Thus, the current-carrying wire produces concentric circular loops of magnetic field. The magnetic field generated by a wire can be...
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
01:17Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
01:17Force On A Current Loop In A Magnetic Field
Magnetic forces on wires carrying current are most frequently applied in motors. A DC motor is a device that converts electrical energy into mechanical work. In motors, wire loops are enclosed in a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate. The direction of the current is reversed once the loop's surface area is lined up with the magnetic field, causing a constant torque on the loop. During the process, commutators...