One of most important developments for city growth was steel strong enough to allow skyscrapers to be built. With these tall buildings, cities confined to a limited amount of area could still grow by building up. Now researchers are trying to do the same thing by developing 3D microchips, and those at the University of Cambridge have finally achieved this.
The typical microchip has a fairly flat design and information within it can only move within a plane. The new microchip though has multiple layers that store information, with messenger layers in between to move the information from one layer to another. The information is not stored electronically but instead utilizes electronic spin, or the magnetic moment of individual electrons. The storage layers are made of cobalt and platinum while ruthenium atoms act as the messengers. Using a laser probe and switching a magnetic field on and off allowed the researchers to watch as information climbed through the layers.
The ability to have information travel through a 3D space like this could greatly affect the world of electronics by enabling much higher data storage densities. To achieve similar movement with today's technology, one would have to employ a series of transistors, which would be much larger than the atoms used in this design.
Source: University of Cambridge