Laser control of magnetism could improve hard drives
A quick laser zap can alter the magnetism of a host of materials, researchers report August 21 in Science. The finding opens up the possibility of using lasers to speed up and simplify data storage in computers.
Computer hard drives read and write data by flipping the magnetization of memory cells with magnetic fields. In 2007, Dutch and Japanese researchers discovered that for a limited set of materials, they could replace the relatively slow, energy-hogging magnetic fields with laser light. The clockwise or counterclockwise polarization of the light determined the direction of the materials’ magnetization.
Physicist Eric Fullerton of the University of California, San Diego and his team decided to shine a rapid-pulse laser at a wider variety of magnetic materials, including those under study for commercial computing applications. He found that many of the materials could also be tuned by the polarization of the light.
One material, a film containing iron and platinum, is already being tested in hard drive prototypes that use lasers as a heat source to make storing data easier. Fullerton’s research suggests that upgrading the lasers to emit quick polarized pulses could enable the laser light to read and write data as well.
C-H. Lambert et al. All-optical control of ferromagnetic thin films and nanostructures. Science. Published online August 21, 2014. doi: 10.1126/science.1253493.
C.D. Stanciu et al. All-optical magnetic recording with circularly polarized light. Physical Review Letters. Vol. 99, July 25, 2007, 047601. doi: 10.1103/PhysRevLett.99.047601.