'Miracle material' for spintronics could keep Moore's law going

May 30, 2017 //By Jean-Pierre Joosting
A University of Utah-led team has discovered that a class of "miracle materials" called organic-inorganic hybrid perovskites could be a game changer for future spintronic devices.

Cellphones, computers and other electronics are currently based on silicon transistors, which are starting to hit a wall in terms of achieving smaller and smaller sizes. Spintronics is a promising alternative that carries information based on the spin of an electron rather than based on electron charge as is the case with transistors. Spintronics would result in much smaller mobile electronics.

Spintronics uses the direction of the electron spin – either up or down – to carry information in ones and zeros. A spintronic device can process exponentially more data than traditional electronics that use the ebb and flow of electrical current to generate digital instructions. But physicists have struggled to make spintronic devices a reality.

The study, published in Nature Physics, is the first to show that organic-inorganic hybrid perovskites are a promising material class for spintronics. The researchers discovered that the perovskites possess two contradictory properties necessary to make spintronic devices work – the electrons' spin can be easily controlled, and can also maintain the spin direction long enough to transport information, a property known as spin lifetime.

"It's a device that people always wanted to make, but there are big challenges in finding a material that can be manipulated and, at the same time, have a long spin lifetime," says Sarah Li, assistant professor in the Department of Physics & Astronomy at the University of Utah and lead author of the study. "But for this material, it's the property of the material itself that satisfies both."


This is a schematic of the ultrafast optics experiment. An initial laser pulse aligns an electron spin along the beam path; the electron spin precesses in an external magnetic field; another time delayed laser pulse detects the spin precession by rotation of its polarization plane (North or Up, South or Down). Upper left: the material structure of the hybrid perovskites. Lower right: typical data shows oscillations induced by spin precession. Image courtesy of Patrick Odenthal.