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Author |
Connolly, M.R.; Bemding, S.J.; Milošević, M.V.; Clem, J.R.; Tamegai, T. |
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Title |
Continuum versus discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+\delta disks |
Type |
A1 Journal article |
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Year  |
2010 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
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Volume |
470 |
Issue |
S:1 |
Pages |
S896-S897 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We have used scanning Hall probe and local Hall magnetometry measurements to map flux profiles in superconducting Bi2Sr2CaCu2O8+δ disks whose diameters span the crossover between the bulk and mesoscopic vortex regimes. The behaviour of large disks (greater-or-equal, slanted20 μm diameter) is well described by analytic models that assume a continuous distribution of flux in the sample. Small disks (less-than-or-equals, slant10 μm diameter), on the other hand, exhibit clear signatures of the underlying discrete vortex structure as well as competition between triangular Abrikosov ordering and the formation of shell structures driven by interactions with circulating edge currents. At low fields we are able to directly observe the characteristic mesoscopic compression of vortex clusters which is linked to oscillations in the diameter of the vortex dome in increasing magnetic fields. At higher fields, where single vortex resolution is lost, we are still able to track configurational changes in the vortex patterns, since competing vortex orders impose unmistakable signatures on local magnetisation curves. Our observations are in excellent agreement with molecular-dynamics numerical simulations which lead us to a natural definition of the lengthscale for the crossover between discrete and continuum behaviour in our system. |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000286075700384 |
Publication Date |
2009-11-20 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0921-4534; |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
1.404 |
Times cited |
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Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 1.404; 2010 IF: 1.415 |
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Call Number |
UA @ lucian @ c:irua:88069 |
Serial |
494 |
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Author |
Connolly, M.R.; Milošević, M.V.; Bending, S.J.; Clem, J.R.; Tamegai, T. |
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Title |
Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
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Volume |
150 |
Issue |
5 |
Pages |
052039 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The magnetic properties of a superconducting disk change dramatically when its dimensions become mesoscopic. Unlike large disks, where the screening currents induced by an applied magnetic field are strong enough to force vortices to accumulate in a 'puddle' at the centre, in a mesoscopic disk the interaction between one of these vortices and the edge currents can be comparable to the intervortex repulsion, resulting in a destruction of the ordered triangular vortex lattice structure at the centre. Vortices instead form clusters which adopt polygonal and shell-like structures which exhibit magic number states similar to those of charged particles in a confining potential, and electrons in artificial atoms. We have fabricated mesoscopic high temperature superconducting Bi2Sr2CaCu2O8+δ disks and investigated their magnetic properties using magneto-optical imaging (MOI) and high resolution scanning Hall probe microscopy (SHPM). The temperature dependence of the vortex penetration field measured using MOI is in excellent agreement with models of the thermal excitation of pancake vortices over edge barriers. The growth of the central vortex puddle has been directly imaged using SHPM and magic vortex numbers showing higher stability have been correlated with abrupt jumps in the measured local magnetisation curves. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
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Publication Date |
2009-04-01 |
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Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1742-6588;1742-6596; |
ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:106137 |
Serial |
3881 |
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Author |
Connolly, M.R.; Milošević, M.V.; Bending, S.J.; Clem, J.R.; Tamegai, T. |
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Title |
Continuum vs. discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+\delta disks |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
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Volume |
85 |
Issue |
1 |
Pages |
17008,1-17008,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Scanning Hall probe and local Hall magnetometry measurements have been used to investigate flux distributions in large mesoscopic superconducting disks with sizes that lie near the crossover between the bulk and mesoscopic vortex regimes. Results obtained by directly mapping the magnetic induction profiles of the disks at different applied fields can be quite successfully fitted to analytic models which assume a continuous distribution of flux in the sample. At low fields, however, we do observe clear signatures of the underlying discrete vortex structure and can resolve the characteristic mesoscopic compression of vortex clusters in increasing magnetic fields. Even at higher fields, where single-vortex resolution is lost, we are still able to track configurational changes in the vortex patterns, since competing vortex orders impose unmistakable signatures on “local” magnetisation curves as a function of the applied field. Our observations are in excellent agreement with molecular-dynamics numerical simulations which lead us to a natural definition of the lengthscale for the crossover between discrete and continuum behaviours in our system. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Paris |
Editor |
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Language |
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Wos |
000263692500029 |
Publication Date |
2009-01-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0295-5075;1286-4854; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.957 |
Times cited |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.957; 2009 IF: 2.893 |
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Call Number |
UA @ lucian @ c:irua:76306 |
Serial |
495 |
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Author |
Connolly, M.R.; Milošević, M.V.; Bending, S.J.; Tamegai, T. |
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Title |
Magneto-optical imaging of flux penetration into arrays of Bi2Sr2CaCu2O8 microdisks |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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Volume |
78 |
Issue |
13 |
Pages |
132501,1-132501,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We have used differential magneto-optical (MO) imaging to investigate the mixed state of superconducting Bi2Sr2CaCu2O8+ (BSCCO) microdisks fabricated on a single-crystal sample. MO difference images of the stray field distribution over a range of out-of-plane fields allow us to distinguish between flux that is penetrating the disks and that entering the underlying BSCCO platelet. We find that flux preferentially flows along linear defects into the interstitial platelet regions up to a characteristic field Hp, above which flux enters the disks. We identify this as the field of first penetration of pancake vortices over the Bean-Livingston barrier around the disks, where Hp(T) at intermediate temperatures is well described by an exponentially decaying function with a characteristic temperature T0=19 K. At a given temperature, a minority of the disks exhibit a lower penetration field and we correlate the location of these disks with the linear defects in the BSCCO crystal. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000260574200018 |
Publication Date |
2008-10-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
8 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2008 IF: 3.322 |
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Call Number |
UA @ lucian @ c:irua:75658 |
Serial |
1901 |
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