Summary: Magnetoresistance of closely packed Ni80Fe20 nanowires
S. Goolaup a
, A.O. Adeyeye a,*, N. Singh a,b
Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering drive 3,
Singapore 117576 Singapore
Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 Singapore
Available online 28 November 2005
In this work, we present a systematic study of the transport properties of Ni80Fe20 nanowire arrays with varied film thicknesses. Closely packed
nanowire arrays of width 185 nm and edge to edge of spacing 35 nm were fabricated using deep ultra-violet (DUV) lithography at 248 nm
exposing wavelength. Our thickness-dependent study reveals a crossover from coherent rotation to curling mode of magnetization for t !80 nm.
This is attributed to the spatially varying demagnetizing field across the wire. The magnetization reversal for fields applied along the hard-axis is
mediated by coherent rotation, for all the thicknesses investigated. We also observed the appearance of exchange bias effect at 4 K, due to the
formation of an anti-ferromagnetic phase.
D 2005 Elsevier B.V. All rights reserved.
Advances in nanofabrication techniques has given rise to a
considerable interest in patterned nanoscale magnetic materials