Modification of Magnetic Anisotropy in Garnets by Ion Implantation

Abstract

Ion implantation into epitaxial films of certain magnetic garnets grown on nonmagnetic substrates has produced layers with uniaxial anisotropy suitable for magnetic ``bubble'' formation and propagation. Implantation of hydrogen or lithium ions causes the garnet lattice to expand and the constraint of the unimplanted material places the implanted layer in lateral compression. In garnets with positive magnetostriction, this stress results in an induced easy axis of magnetization perpendicular to the surface. Helium-ion implantation does not cause lattice expansion or induce magnetic anisotropy. This suggests that the phenomenon is due to a chemical effect rather than lattice damage.