TY - JOUR
T1 - Microwave absorption of patterned arrays of nanosized magnetic stripes with different aspect ratios
AU - Malkinski, Leszek M.
AU - Yu, Minghui
AU - Vovk, Andriy Y.
AU - Scherer, Donald J.
AU - Spinu, Leonard
AU - Zhou, Weilie
AU - Whittenburg, Scott
AU - Davis, Zachary
AU - Jung, Jin Seung
PY - 2007
Y1 - 2007
N2 - Arrays consisting of nanosized stripes of Permalloy with different length-to-width ratios have been fabricated using electron beam nanolithography, magnetron sputtering, and lift-off process. These stripes have a thickness of 100 nm, a width of 300 nm, and different lengths ranging from 300 nm to 100 μm. The stripes are separated by a distance of 1 μm. Magnetization hysteresis loops were measured using a superconducting quantum interference device susceptometer. Microwave absorption at 9.8 GHz was determined by means of ferromagnetic resonance technique. The dependence of the resonant field on the angle between the nanostructure and the in-plane dc magnetic field indicates the presence of uniaxial magnetic anisotropy associated with the aspect ratio of the stripes. A maximum change of the resonant field of 1600 Oe was observed in the longest stripes, yet it was only 200 Oe for square shaped stripes. The linewidth of the resonant curve varied with the angle, in the range from 120 to 300 Oe. Most of the ferromagnetic resonance spectra exhibited multiple resonant peaks due to dimensional confinement of spin waves in the nanosized stripes. The maximum squareness of the magnetization hysteresis loop was for the field applied along the stripes, but the coercivity did not have a monotonic angular dependence as expected from the Stoner-Wohlfarth model for coherent magnetization rotation of the systems with uniaxial anisotropy.
AB - Arrays consisting of nanosized stripes of Permalloy with different length-to-width ratios have been fabricated using electron beam nanolithography, magnetron sputtering, and lift-off process. These stripes have a thickness of 100 nm, a width of 300 nm, and different lengths ranging from 300 nm to 100 μm. The stripes are separated by a distance of 1 μm. Magnetization hysteresis loops were measured using a superconducting quantum interference device susceptometer. Microwave absorption at 9.8 GHz was determined by means of ferromagnetic resonance technique. The dependence of the resonant field on the angle between the nanostructure and the in-plane dc magnetic field indicates the presence of uniaxial magnetic anisotropy associated with the aspect ratio of the stripes. A maximum change of the resonant field of 1600 Oe was observed in the longest stripes, yet it was only 200 Oe for square shaped stripes. The linewidth of the resonant curve varied with the angle, in the range from 120 to 300 Oe. Most of the ferromagnetic resonance spectra exhibited multiple resonant peaks due to dimensional confinement of spin waves in the nanosized stripes. The maximum squareness of the magnetization hysteresis loop was for the field applied along the stripes, but the coercivity did not have a monotonic angular dependence as expected from the Stoner-Wohlfarth model for coherent magnetization rotation of the systems with uniaxial anisotropy.
UR - http://www.scopus.com/inward/record.url?scp=34248586855&partnerID=8YFLogxK
U2 - 10.1063/1.2712820
DO - 10.1063/1.2712820
M3 - Article
AN - SCOPUS:34248586855
SN - 0021-8979
VL - 101
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 9
M1 - 09J110
ER -