Irradiation for Magnetic Order

APPLIED PHYSICS The distinction between the binary states zero and one in a magnetic memory device is determined by the orientation of the magnetization in the bit. Information storage density benefits from making the memory elements smaller, but as the memory elements decrease in size, the distinction between the one and zero states can become blurred because the energy barrier, or anisotropy, also tends to be reduced. Woods et al. present a post-growth and post-patterning technique that can be used to redirect and imprint the magnetic anistropy in thin-film structures. Irradiation of magnetic films with 200-kiloelectron-volt argon ions while a saturating magnetic field was applied fixed the orientation and extent of separation of the easy and hard axes. The technique should provide a route to satisfy the demand for further reduction in the size of magnetic storage devices. — ISO Appl. Phys. Lett . 81 , 1267 (2002).