Synopsis: Island adventure

In a prototype spintronics device, a magnetic island keeps electrons’ spins polarized as they traverse a semiconductor strip.
Synopsis figure
Credit: Courtesy of D. Awschalom, University of California, Santa Barbara

Spintronics is a discipline that seeks to exploit the spin dimension for novel electronic applications. Typically, timed pulses of light at optical or microwave frequencies are used to control the direction of a spin or ensemble of spins; but maintaining the coherence of the spins as they are transported through a device has proven challenging.

Writing in Physical Review Letters, Mark Nowakowski and colleagues from the University of California, Santa Barbara, with collaborators at Pennsylvania State University, both in the US, demonstrate a method for controlling the direction of the spin of an ensemble of electrons as they travel through a semiconductor. The sample is a GaAs channel with an island of MnAs in the middle. Polarizing the nuclei under the MnAs island, either electrically or optically, creates a localized effective magnetic field. When an optically injected spin ensemble created at one end of the GaAs strip traverses the MnAs region, the electrons precess faster due to the effective magnetic field. The authors achieve an increase in rotation angle of the moving spins by 5π radians over a distance of 30 microns. By making a second sample with an electrical contact to the MnAs island, the authors also demonstrate the ability to control the nuclear field strength electrically, highlighting the versatility of their approach. – Daniel Ucko


Announcements

More Announcements »

Subject Areas

Spintronics

Previous Synopsis

Cosmology

Cosmic nudity

Read More »

Next Synopsis

Atomic and Molecular Physics

Floating and spinning graphene

Read More »

Related Articles

Synopsis: Magnon Drag
Spintronics

Synopsis: Magnon Drag

Quantized spin waves known as magnons could experience a drag-like phenomenon in two spatially separated ferromagnetic layers. Read More »

Synopsis: With Heat Comes Current
Spintronics

Synopsis: With Heat Comes Current

Researchers have observed spin-dependent thermoelectric currents in superconductors—a finding that could lead to precise cryogenic thermometers. Read More »

Synopsis: Spin Currents in Antiferromagnets
Magnetism

Synopsis: Spin Currents in Antiferromagnets

Experiments show that a heat gradient can generate a spin-wave spin current in an antiferromagnetic insulator. Read More »

More Articles