Strong vortex core pinning and Barkhausen-free magnetization response in thin Permalloy disks induced by implantation of 1 × 104 Ga + ions

Abstract

Artificial vortex core pinning sites are induced in thin Permalloy disks by point exposure to as few as 10 000 ions from a focused Ga+ beam. These pinning sites yield a first-order change in the magnetization response of the disk. A single site can keep the vortex core pinned over an applied field range comparable to the vortex annihilation field of the unaltered disk. Several widely separated sites can work together to keep the core pinned in one place, while the Barkhausen effect is eliminated from the magnetization curve over a range approaching the saturation moment of the disk. © 2014 AIP Publishing LLC.

Publication
J. Appl. Phys.