Ever lose data because your computer loses power? Chia-Ling Chien, a professor of physics at the Krieger School of Arts and Sciences at Johns Hopkins University, may have a solution. He developed a new chromium dioxide material called "half-metallic ferromagnet" that could change the way computer memory works. Computer memory currently uses dynamic random access memory (DRAM). Chien's material enables a new technology called magnetic random access memory (MRAM), which he says will allow retention of data even when power is lost. "Capacitors in current memory systems leak and have to be refreshed to prevent data loss," says Chien. "MRAM relies on magnetic orientation. Loss of power would not mean a loss of the data it stores," he says. MRAM harnesses the power of the electron's spin, a characteristic that conventional electronic circuits do not use. Electronic spin and a material's magnetic property are linked. The new chromium dioxide material is 96% spin-polarized, meaning that nearly all electrons spin in the same orientation. The spin-polarized material is thought to be useful in electrodes, where controlling the magnetization makes the junction switch between high and low electrical resistance. For more information, go to www.pha.jhu.edu.
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