Imagine biting into a peanut butter sandwich and
discovering a slice of cheese tucked between the bread and the
butter. In a way, this is what happened to a team of physicists at
the University of Arizona, except the “cheese” was a layer of iron
oxide, less than one atomic layer thick, and the “sandwich” was a
magnetic tunnel junction—a tiny, layered structure of exotic
materials that someday may replace current silicon-based computer
transistors and revolutionize computing. Iron oxide—a material
related to what is commonly known as rust—exhibits exotic
properties when its thickness approaches that of single
atoms.
