Correlation of Edge Roughness to Nucleation Field and Nucleation Field Distribution in Patterned Permalloy Elements
June W. Lau, Robert D. McMichael, M A. Schofield, Y Zhu
A direct consequence of shrinking technology down into the nanoscale is the steadily increasing boundary to volume ratio. In the case of magnetic nanostructures, this trend emphasizes the role of edges on switching behavior. Magnetic nanostructures have already realized the magnetic random accessed memory (MRAM) technology and remain promising for patterned-bit-media hard-drives with storage densities >1 Tb/in2 . Ideally for both technologies, each bit, a physically isolated nano-island of magnetic material, would have identical writing (magnetic switching) fields as all the other bits within a patterned array if they were identical. In reality, there exists a range in switching conditions, (a.k.a. switching field distribution, or SFD) due to subtle differences among the bits on the nanoscale. It is important for these industries to understand the origin of the SFD because a SFD reduces both the areal density and memory reliability. In this work, we examine edge-roughness as a source of non-uniformity on the nanoscale, and found direct correlations to both the switching field and the SFD required to initiate a specific mode of switching, i.e. vortex nucleation. These results bridge an important gap in the understanding of how physical edge attributes alter switching behavior.
edge roughness, magnetic random access memory, MRAM, nucleation field Permalloy elements
, McMichael, R.
, Schofield, M.
and Zhu, Y.
Correlation of Edge Roughness to Nucleation Field and Nucleation Field Distribution in Patterned Permalloy Elements, Nature Nanotechnology
(Accessed September 27, 2023)