Communications of the ACM
Spintronic Devices Possible Without Magnetic Material
A researcher at Argonne National Laboratory stumbled upon the discovery that a magnetic material may not be required in order to generate spin current from insulators.
Credit: Argonne National Laboratory
Argonne National Laboratory researcher Stephen Wu has found it may be possible to generate spin current from insulators without a magnetic material, a discovery that could lead to the development of more powerful computers.
The discovery was made as Wu was examining different materials to produce smaller spintronic devices and provide greater control over thermal gradients, which need to be applied to the material to start the current spin of the electrons. Wu's discovery involved yttrium iron garnet (YIG) on a substrate of paramagnetic gadolinium gallium garnet (GGG). Because GGG is a paramagnet and not a ferromagnet, Wu did not expect to see any spin because the paramagnet does not generate a magnetic field. However, Wu and other researchers observed the spin current was stronger in the GGG than in the YIG.
"We think that there may be other new physics working here," says Argonne physicist Anand Bhattacharya.
The researchers see an opportunity to push ahead the state of the art in spintronics even though the physics behind it are not fully understood.
"In a spintronic device you don't have to use a ferromagnet," Wu says. "You can use either a paramagnetic metal or a paramagnetic insulator to do it now."
From IEEE Spectrum
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