The Effect of Spreading Resistance on the Magnetoresistance of Current-Perpendicular-to-Plane Spin Valves With Patterned Layers

• Published in: IEEE transactions on magnetics Vol. 42; no. 11; pp. 3788 - 3790
• Main Authors: Kumar, S.B., Jalil, M.B.A., Tan, S.G., Ng, R., Liew, T.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-11-2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analytical models; CPP; Cross-disciplinary physics: materials science; rheology; Electric resistance; Equations; Exact sciences and technology; Finite element methods; Giant magnetoresistance; Magnetic materials; Magnetism; Magnetoresistance; Magnetoresistivity; Material storage; Materials science; Mathematical models; Other topics in materials science; Pattern analysis; Patterning; Physics; resistance; Solvers; Spacers; spin valve; Spin valves; Spreading; Strontium; CPP; spreading; Valves; Magnetic materials; Magnetoresistance; spin valve; resistance; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2006.884833

We derived the magnetoresistance (MR) that takes into consideration the effect of spreading resistance (SR) due to the patterned layer in a spin-valve (SV) structure. Our analysis is based on the: 1) spin drift diffusion (SDD) model and 2) finite-element Poisson (FEP) solver. The SDD model does not take into consideration the effect of SR due to patterning, whereas FEP includes the effect of SR. This enables us to compare and analyze the contribution of both patterning and SR to the MR of the device. In a FM-NM-FM structure, the NM layer was patterned into: 1) single and 2) multiple cylindrical structure. We found that the spacer patterning and the resulting SR causes a significant increase (by >50%) of MR at low area ratio (A R ) of the patterned layer. Yet, MR of patterned structure is lower compared to the MR of original structure. However, patterning of a FM layer inserted within the NM spacer results in significantly higher MR