Scientists have precisely measured a key parameter of electron interactions called non-adiabatic spin torque that is essential to the future development of spintronic devices. Not only does this unprecedented precision guide the reading and writing of digital information, but it defines the upper limit on processing speed that may underlie a spintronic revolution.

Most prevailing technology fails to take full advantage of the electron, which features intrinsic quantum variables beyond the charge and flow driving electricity. One of these, a parameter known as spin direction, can be strategically manipulated to function as a high-density medium to store and transmit information in spintronics. But as any computer scientist can attest, dense data can mean very little without enough speed to process it efficiently.

Consider the behavior of coffee stirred rapidly in a mug: the motion of a spoon causes the liquid to spin, rising along the edges and spiraling low in the center. Because the coffee can’t escape through the mug’s porcelain walls, the trapped energy generates the cone-like vortex in the center. A similar phenomenon can be produced on magnetic materials to reveal fundamental quantum measurements.The Brookhaven physicists applied a range of high-frequency electric currents to a patterned film called permalloy, useful for its high magnetic permeability. This material, 50 nanometers (billionths of a meter) thick and composed of nickel and iron, was designed to strictly contain any generated magnetic field. Unable to escape, trapped electron spins combine and spiral within the permalloy, building into an observable and testable phenomenon called a magnetic vortex core.

The Brookhaven physicists applied a range of high-frequency electric currents to a patterned film called permalloy, useful for its high magnetic permeability. This material, 50 nanometers (billionths of a meter) thick and composed of nickel and iron, was designed to strictly contain any generated magnetic field. Unable to escape, trapped electron spins combine and spiral within the permalloy, building into an observable and testable phenomenon called a magnetic vortex core.

The high-speed, high-density hard drives in today’s computers write information into spinning disks of magnetic materials, using electricity to toggle between magnetic polarity states that correspond to the “1” or “0” of binary computer code. But a number of intrinsic problems emerge with this method of data storage, notably limits to speed because of the spinning disk, which is made less reliable by moving parts, significant heat generation, and the considerable energy needed to write and read information.

Beyond that, magnetic storage suffers from a profound scaling issue. The magnetic fields in these devices exert influence on surrounding space, a so-called fringing field. Without appropriate space between magnetic data bits, this field can corrupt neighboring bits of digital information by inadvertently flipping “1” into “0.” This translates to an ultimate limit on scalability, as these data bits need too much room to allow endless increases in data density.

One pioneering spintronic prototype is IBM’s Racetrack memory, which uses spin-coherent electric current to move magnetic domains, or discrete data bits, along a permalloy wire about 200 nanometers across and 100 nanometers thick. The spin of these magnetic domains is altered as they pass over a read/write head, forming new data patterns that travel back and forth along the nanowire racetrack. This process not only yields the prized stability of flash memory devices, but also offers speed and capacity exceeding disk drives.

The new measurement pins down a fundamental limit on data manipulation speeds, but the task of translating this work into practical limits on processor speed and hard drive space will fall to the scientists and engineers building the next generation of digital devices.

This story is reprinted from material from Brookhaven National Lab, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.