Researchers Helping to Validate Spintronics

Scientists at the University of Delaware, Newark, say that they have confirmed the presence of a magnetic field generated by electrons, which scientists had theorized existed, but had never been proven until now. This finding, they say, could help to lay the groundwork for electronics of the future. Their finding expands the potential for harnessing the "spin" or magnetic properties of electrons, which adds a fundamental new building block to the pioneering field of spintronics.

Semiconductors carry along the electrical charge of electrons, but don’t use the magnetic or "spin" properties of the subatomic particles. They report that in the presence of a magnet, an electron will spin up or down, correlating to the binary states of 1 or 0 that computers use to encode and process data. One spin state aligns with the magnetic field, and one opposes it. A spintronics device requires an excess number of either spin-up or spin-down electrons. Controlling the direction of the magnetization is a major goal in the fledgling field.

In the past, scientists were able to generate a spin current in which electrons with opposite spins move in opposite directions by passing an electrical current through a non-magnetic heavy metal.

But, in a double layer of heavy metal and ferromagnetic material, the pure spin current will diffuse into the ferromagnetic material. When this occurs, the Delaware team has detected a magnetic field that can switch the material's magnetization.

This magnetic field is confined inside the ferromagnetic material unlike the conventional magnetic field generated from a magnet, which is difficult to shield. They say that they now have a means of generating a magnetic field and controlling the direction of a nanomagnet, as well as a new measurement technique to characterize the magnetic field.