Irish researchers’ new device could answer mass storage problem

21 Jul 2016

Researchers from Trinity College Dublin (TCD) have announced the creation of a device that promises to revolutionise mass data storage by removing the need to generate a magnetic field.

The device was developed by a team of researchers from the AMBER centre in TCD, comprising two PhD students and a number of senior researchers who were developing a high-density storage method referred to as magnetoresistive RAM, or MRAM.

Despite being in development since the 1990s, little progress has been made in bringing MRAM to market because of the significant costs and complexity of large-scale manufacturing.

Future Human

What is MRAM?

Information stored on a typical RAM chip during a computer session is lost once the computer has been turned off (unless it has been transferred to the hard drive) because this data is stored using an electrical charge.

In MRAM, however, data is stored using a magnetic charge, meaning that it is not erased when the device is turned off and offering a huge potential for both speed and storage capacity of devices.

One limitation found within MRAM chips, though, is the need to generate a magnetic field, which is costly and requires more energy.

Zero-cost in energy

What makes the TCD team’s latest breakthrough so significant is that its new device can circumvent the need to generate a magnetic field, resulting in a zero-cost in energy.

PhD researchers Yong Chang Lau and Davide Betto created their device using a stack of five metal layers, each of them a few nanometres thick. At the bottom is a layer of platinum beneath the iron-based magnetic storage layer, which is just six atoms thick.

By passing a current through the platinum, the electrons separate into two groups with their magnetism pointing in opposite directions at the top and bottom surfaces thanks to an effect known as spin-orbit torque.

However, when the top electrons are then pumped into the storage layer, they try to switch its magnetic direction. At this point, the magnetism of the storage layer is indeterminate – think of a pencil balanced on its point, not knowing which way it will fall. To address this issue, the team designed the rest of the stack to act like a nanoscale permanent magnet that creates the small field necessary to make the switching determinate.

The next step for the researchers is to demonstrate a full memory cell, and an ultra-fast oscillator based on spin-orbit torque using layers of an experimental magnetic alloy.

The team published these findings in Nature Nanotechnology.

Abstract data centre image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic