Nanoscale 3D Spintronic Memory Chip Created for First Time
Scientists constructed an experimental version of a new kind of nanoscale 3D microchip that allows to store data in many layers upwards and without transistors, both a radically new way of building memory chips. On top of that, the Cambridge scientists used a spintronic (spin transport electronic) chip in their research, which exploits the electron's tiny magnetic moment or spin instead of the charge-based electronic technology used in most of today's microchips - although spintronics are already in use and will become the standard "in the next few years", according to the researchers.
The new memory chip is constructed with nanotechnology tools (sputtering) and can pass data in the form of spinning electrons in all directions, not just in a two dimensional plane like current chips (which can still consist of several, but not an extreme amount of, layers of transistors stacked on each other).
The foundation is a silicon chip, on which layers of cobalt, platinum, and ruthenium atoms are built, with each layer just a few atoms thick, which means few nanometers. The cobalt and platinum atoms store the digital information while the ruthenium atoms act as messengers, communicating that information between neighboring layers of cobalt and platinum.
The scientists then used a laser technique called MOKE to probe the data content of the different layers. As they switched a magnetic field on and off they saw in the MOKE signal the data climbing layer by layer from the bottom of the chip to the top. They then confirmed the results using a different measurement method.
"Each step on our spintronic staircase is only a few atoms high," said Professor Russell Cowburn, lead researcher of the study from the Cavendish Laboratory at the University of Cambridge's Department of Physics. "I find it amazing that by using nanotechnology, not only can we build structures with such precision in the lab, but also using advanced laser instruments, we can actually see the data climbing this nano-staircase step by step."
"This is a great example of the power of advanced materials science. Traditionally, we would use a series of electronic transistors to move data like this. We've been able to achieve the same effect just by combining different basic elements such as cobalt, platinum and ruthenium. This is the 21st century way of building things - harnessing the basic power of elements and materials to give built-in functionality."
The research was funded by the European Research Council, the Isaac Newton Trust, and the Netherlands Organisation for Scientific Research (NWO).
Paper: Reinoud Lavrijsen et al., Magnetic ratchet for three-dimensional spintronic memory and logic, Nature, 2013, DOI: 10.1038/nature11733