Friday, February 22, 2008
The design of atomic-scale magnetic memories got a boost Friday (Feb. 22) with an announcement from IBM Corp. researchers that they have manipulated individual cobalt atoms. The first successful characterization of the force required to move magnetic atoms on a surface suggests that IBM's technique is a prelude to future bit-cells holding just a few atoms. Even the densest magnetic memories use 1 million or more atoms to store a single bit. However, last fall IBM's Almaden Research Center (San Jose, Calif.) demonstrated how to measure a single atom's ability to store a bit, called magnetic anisotropy. That demonstration used a scanning tunneling microscope (STM) to send a current through a cobalt atom. However, sending a current tunneling through an atom using STM requires placing it on an insulating monolayer measuring only one-atom thick. Since then, IBM researchers discovered that such thin insulating layers will not work for storing bits on cobalt atoms. Instead, thick insulators are required that preclude the tunneling action of STMs. Hence, Almaden scientists had to devise a different method for moving cobalt atoms into place for future atomic-scale memories.
Posted by R. Colin Johnson at 8:23 AM