No more long boots
6 Nov 2001
A University of Florida-led research team has created one of the first practical magnetic semiconductors made with materials commonly used in high-speed electronics, a notable advance in a hot new field known as 'spintronics.'
Today's semiconductors work by exploiting the electric charge attached to electrons. But electrons in solids have another fundamental property known as 'spin,' which makes them act like small magnets.
In the past, however, semiconductors have displayed magnetism only at impractically low temperatures of hundreds of degrees below zero Fahrenheit, according to Stephen Pearton, a UF professor of materials science at the University.
Researchers had been slowly chipping away at that limitation until last year, when a prominent scientist in the field predicted that a certain class of semiconductors would exhibit magnetism at room temperature. His words jump-started new research; at least two groups have proven him correct and achieved room temperature magnetism in recent months, Pearton said.
The rapid progress and excitement in the field has closely tracked similar advances in superconductors of a decade ago, Pearton said. The hitch in the latest research is that the semiconductors achieving magnetism at warm temperatures are made of exotic materials not seen in typical semiconductor production, making them impossible or unlikely candidates for commercialization in computer chips or other applications.
The UF-led team - five materials engineers and four physicists at UF - achieved magnetism using gallium phosphide 'doped,' or infused, with manganese. In addition, the researchers' method, called molecular beam epitaxy, is standard in the chip and electronics industry, Pearton said.
The team first reported achieving magnetism at about 100 degrees below zero Fahrenheit. But while that represented progress, it's still too cold to be easily commercialised. But further results achieved by the UF team this week show magnetism in the manganese-doped phosphide semiconductor at temperatures that exceed room temperature.
'This makes it less of a leap of faith that practical spin-electronic devices could actually be manufactured,' Pearton said.
