Spintronics: The answer to Moore's Law

In a 1965 paper, Intel co-founder Gordon E Moore described how the number of transistors that could be placed inexpensively on an integrated circuit had doubled every year between 1958 and 1965. He predicted the trend would continue for at least 10 more years. That prediction, now known as Moore’s Law, effectively described a trend that has continued ever since, but the end of that trend—the moment when transistors are as small as atoms, and cannot be shrunk any further—is expected as early as 2015.

Researchers are now seeking new concepts of electronics that sustain the growth of computing power. One such step is research at the Cavendish Laboratory, the University of Cambridge’s Department of Physics, which provides new insight into spintronics, which has been hailed as the successor to the transistor.

While conventional technology relies on harnessing the charge of electrons, the field of spintronics depends instead on the manipulation of electrons’ spin. One of the unique properties in spintronics is that spins can be transferred without the flow of electric charge currents. This is called ‘spin current’, and unlike other concepts of harnessing electrons, the spin current can transfer information without generating heat in electric devices. The major remaining obstacle to a viable spin current technology is the difficulty of creating a volume of spin current large enough to support current and future electronic devices.

Spintronics, which exploits the electron’s tiny magnetic moment, or ‘spin’, could radically change computing due to its potential of high-speed, high-density and low-power consumption. The new research sheds light on how to make ‘spin’ more efficient.

Scientists began developing new spin-based electronics, beginning with the discovery in 1988 of giant magnetoresistance (GMR) effect. The discovery of the GMR effect brought about a breakthrough in gigabyte hard disk drives, and was also important in the development of portable electronic devices such as the iPod. The new Cambridge researchers—in collaboration with Sergej Demokritov’s group at the University of Münster, Germany—have used the collective motion of spins called spin waves (the wave property of spins). By bringing spin waves into interaction, they have demonstrated a new, more efficient way of generating spin current.