‘Spin Current’ Seen in Motion for the 1st time

This illustration shows the flow of a magnetic property of electrons known as spin current from a magnetic material (blue), to a nonmagnetic material (red). Credit: SLAC National Accelerator Laboratory

The result, which revealed a surprising loss of current along the way, is an important step toward realizing next-gen “Spintronics”. Spin current is an inherent magnetic property common to all electrons – as it travels across materials. Modern computing relies on the precise control of electric charges that zip around from component to component in labyrinth-like channels in semiconductors. Spintronics could change that by tapping electrons’ spin, with “up” or “down” orientation, rather than their charge.

Finding a way to directly control this up or down property would rule out the need to flow electric charge in computer chips. Devices like laptops and smartphones would use less battery power and wouldn’t get so hot during use, and could also access data more quickly. But the movement of this magnetic spin current had only been measured indirectly until a SLAC-led team found a way to directly observe it using X-rays. This could be useful in guiding material selection to improve spintronics performance.

They created a spintronics test device that flowed the spin current from a cobalt-based magnetic material across copper, (nonmagnetic). “What we really didn’t know was how this magnetization flowed from one material to another,” Ohldag said, “and that is what we saw for the first time.” But they also found current loses > half of its magnetic spin strength as it travels from magnetic to nonmagnetic material.

To make spintronics devices more effective for commercial applications, they will need to limit this loss of spin current at the interface between materials. “We can explore different materials and interfaces that are of different qualities and roughness,” he said. https://www6.slac.stanford.edu/news/2015-09-03-researchers-see-spin-current-motion-first-time.aspx

This illustration shows the flow of a magnetic property of electrons known as spin current from a magnetic material (blue), to a nonmagnetic material (red). (SLAC National Accelerator Laboratory) https://www6.slac.stanford.edu/news/2015-09-03-researchers-see-spin-current-motion-first-time.aspx