Distribution of vortices in Nb/Al multilayers studied by spin-polarized neutron reflectivity and magnetization

S. W. Han; J. Farmer; P. F. Miceli; G. Felcher; R. Goyette; G. T. Kiehne; J. B. Ketterson

doi:10.1016/S0921-4526(03)00286-2

Distribution of vortices in Nb/Al multilayers studied by spin-polarized neutron reflectivity and magnetization

S. W. Han, J. Farmer, P. F. Miceli, G. Felcher, R. Goyette, G. T. Kiehne, J. B. Ketterson

Research output: Contribution to journal › Conference article › peer-review

3 Scopus citations

Abstract

We present SPNR and DC magnetization studies of non-uniformly distributed vortices in Nb/Al multilayers for fields applied near-parallel to the film surface. Peaks are observed in the M-H curves that are shown to correspond to vortex row-transitions and the field values of the transitions agree well with free energy calculations. An additional peak is observed at an applied field smaller than the first row-transition field and this is shown to arise from the lower critical field parallel to the surface. Demagnetization effects are discussed. SPNR measurements performed at low field give the London penetration length and measurements in the mixed state are consistent with a single row of vortices residing in the film center, but with positional fluctuations amounting to 1/4 of the film thickness. It is also shown that cycling the applied field leads to a surface-induced reorientation of the vortex magnetic field, which points perpendicular to the surface in zero field.

Original language	English
Pages (from-to)	162-172
Number of pages	11
Journal	Physica B: Physics of Condensed Matter
Volume	336
Issue number	1-2
DOIs	https://doi.org/10.1016/S0921-4526(03)00286-2
State	Published - Aug 2003
Externally published	Yes
Event	Proceedings of the 7th SXNS - Lake Tahoe, CA, United States Duration: Sep 23 2002 → Sep 27 2002

Funding

Support is gratefully acknowledged (P.F.M., S.W.H.) from the Midwest Superconductivity Consortium (MISCON) under DOE grant DE-FG02-90ER45427, the National Science Foundation under grant DMR96-23827, and the University of Missouri Research Board. The Intense Pulsed Neutron Source and work at Argonne National Laboratory is funded by the U.S. Department of Energy, BES-Materials Sciences, under Contract W-31-109-Eng-38. Research at Northwestern University is supported by the Northwestern Materials Research Center through the National Science Foundation-MRSEC program under grant DMR-9632472.

Funders	Funder number
BES-Materials Sciences	W-31-109-Eng-38
Midwest Superconductivity Consortium
National Science Foundation-MRSEC	DMR-9632472
Northwestern Materials Research Center
University of Missouri Research Board
National Science Foundation	DMR96-23827
U.S. Department of Energy	DE-FG02-90ER45427
Argonne National Laboratory

Keywords

Nb/Al multilayers, Superconductivity
SPNR
Spin-polarized neutron reflectivity

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10.1016/S0921-4526(03)00286-2

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title = "Distribution of vortices in Nb/Al multilayers studied by spin-polarized neutron reflectivity and magnetization",

abstract = "We present SPNR and DC magnetization studies of non-uniformly distributed vortices in Nb/Al multilayers for fields applied near-parallel to the film surface. Peaks are observed in the M-H curves that are shown to correspond to vortex row-transitions and the field values of the transitions agree well with free energy calculations. An additional peak is observed at an applied field smaller than the first row-transition field and this is shown to arise from the lower critical field parallel to the surface. Demagnetization effects are discussed. SPNR measurements performed at low field give the London penetration length and measurements in the mixed state are consistent with a single row of vortices residing in the film center, but with positional fluctuations amounting to 1/4 of the film thickness. It is also shown that cycling the applied field leads to a surface-induced reorientation of the vortex magnetic field, which points perpendicular to the surface in zero field.",

keywords = "Nb/Al multilayers, Superconductivity, SPNR, Spin-polarized neutron reflectivity",

author = "Han, {S. W.} and J. Farmer and Miceli, {P. F.} and G. Felcher and R. Goyette and Kiehne, {G. T.} and Ketterson, {J. B.}",

year = "2003",

month = aug,

doi = "10.1016/S0921-4526(03)00286-2",

language = "English",

volume = "336",

pages = "162--172",

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issn = "0921-4526",

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note = "Proceedings of the 7th SXNS ; Conference date: 23-09-2002 Through 27-09-2002",

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TY - JOUR

T1 - Distribution of vortices in Nb/Al multilayers studied by spin-polarized neutron reflectivity and magnetization

AU - Han, S. W.

AU - Farmer, J.

AU - Miceli, P. F.

AU - Felcher, G.

AU - Goyette, R.

AU - Kiehne, G. T.

AU - Ketterson, J. B.

PY - 2003/8

Y1 - 2003/8

N2 - We present SPNR and DC magnetization studies of non-uniformly distributed vortices in Nb/Al multilayers for fields applied near-parallel to the film surface. Peaks are observed in the M-H curves that are shown to correspond to vortex row-transitions and the field values of the transitions agree well with free energy calculations. An additional peak is observed at an applied field smaller than the first row-transition field and this is shown to arise from the lower critical field parallel to the surface. Demagnetization effects are discussed. SPNR measurements performed at low field give the London penetration length and measurements in the mixed state are consistent with a single row of vortices residing in the film center, but with positional fluctuations amounting to 1/4 of the film thickness. It is also shown that cycling the applied field leads to a surface-induced reorientation of the vortex magnetic field, which points perpendicular to the surface in zero field.

AB - We present SPNR and DC magnetization studies of non-uniformly distributed vortices in Nb/Al multilayers for fields applied near-parallel to the film surface. Peaks are observed in the M-H curves that are shown to correspond to vortex row-transitions and the field values of the transitions agree well with free energy calculations. An additional peak is observed at an applied field smaller than the first row-transition field and this is shown to arise from the lower critical field parallel to the surface. Demagnetization effects are discussed. SPNR measurements performed at low field give the London penetration length and measurements in the mixed state are consistent with a single row of vortices residing in the film center, but with positional fluctuations amounting to 1/4 of the film thickness. It is also shown that cycling the applied field leads to a surface-induced reorientation of the vortex magnetic field, which points perpendicular to the surface in zero field.

KW - Nb/Al multilayers, Superconductivity

KW - SPNR

KW - Spin-polarized neutron reflectivity

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U2 - 10.1016/S0921-4526(03)00286-2

DO - 10.1016/S0921-4526(03)00286-2

M3 - Conference article

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SN - 0921-4526

VL - 336

SP - 162

EP - 172

JO - Physica B: Physics of Condensed Matter

JF - Physica B: Physics of Condensed Matter

IS - 1-2

T2 - Proceedings of the 7th SXNS

Y2 - 23 September 2002 through 27 September 2002

ER -

Distribution of vortices in Nb/Al multilayers studied by spin-polarized neutron reflectivity and magnetization

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