Tilted nanomagnets open door for advances in computing

A team from the University of California, Berkeley, has discovered a way to reverse the polarisation of nanomagnets without using a magnetic field, opening up the possibility of faster and more energy efficient computing.


This image taken from a computer simulation shows nanomagnets tilted at various angles, with the white regions indicating greater angles of tilt. Researchers have found that even a small tilt of 2 degrees will facilitate magnetic switching.
This image taken from a computer simulation shows nanomagnets tilted at various angles, with the white regions indicating greater angles of tilt. Researchers have found that even a small tilt of 2 degrees will facilitate magnetic switching.

The research, published in the Proceedings of the National Academy of Sciencesmeans that the high-density storage of computers could now be incorporated directly into the circuits that perform calculations. This would significantly reduce energy dissipation, increasing the speed of those calculations and improving computer performance.

“To reduce the power draw and increase the speed, we want to be able to manufacture a computer chip that includes memory so that it is close to the computational action,” said Sayeef Salahuddin, an associate professor of electrical engineering and computer sciences, and head of the research team at Berkley.  

“However, the physics needed to create long-term storage are not compatible with integrated circuits.”

As current passes through a strip of tantalum, electrons with opposite spins separate. Researchers used the resulting polarisation to create a nanomagnetic switch
As current passes through a strip of tantalum, electrons with opposite spins separate. Researchers used the resulting polarisation to create a nanomagnetic switch.

Creating a magnetic field for long-term magnetic memory requires power and space, which is why up until now computational and storage systems have always been separate.

Previously, Salahuddin and his colleagues had discovered that passing a current through the rare metal tantalum creates polarity in magnets without an external magnetic field. However, packing them extremely close together on a chip negated this effect. In its latest research, the team discovered that by tilting the nanomagnets slightly, they could be aligned in close proximity yet retain the desired properties.

“We found that by tilting the magnet – just 2 degrees was enough – you get all the benefits of a high-density magnetic switch without the need for an external magnetic field,” said Salahuddin.