排序方式: 共有19条查询结果,搜索用时 15 毫秒
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Van de Vondel J Gladilin VN Silhanek AV Gillijns W Tempere J Devreese JT Moshchalkov VV 《Physical review letters》2011,106(13):137003
We investigated experimentally the frequency dependence of a superconducting vortex ratchet effect by means of electrical transport measurements and modeled it theoretically using the time-dependent Ginzburg-Landau formalism. We demonstrate that the high frequency vortex behavior can be described as a discrete motion of a particle in a periodic potential, i.e., the so-called stepper-motor behavior. Strikingly, in the more conventional low frequency response a transition takes place from an Abrikosov vortex rectifier to a phase slip line rectifier. This transition is characterized by a strong increase in the rectified voltage and the appearance of a pronounced hysteretic behavior. 相似文献
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J. Van de Vondel A.V. Silhanek V.V. Moshchalkov B. Ilic J. Fields V. Metlushko 《Physica C: Superconductivity and its Applications》2010,470(19):857-859
In this work we present experimental results on the rectification of vortices in a superconductor/ferromagnet system under a high frequency drive. The two-dimensional pinning landscape, induced by the stray fields of the ferromagnetic template, has no intrinsic asymmetry. Nevertheless, an asymmetric potential is artificially induced by an applied dc bias. The experimental results unambiguously show a biased, discrete motion of the vortices in the periodic potential at frequencies above 10 MHz. This synchronized motion is very sensitive to the external applied field. Increasing temperature leads to a reduction of the pinning potential, which in turn results in a lower ac power needed to drive the vortex lattice. 相似文献
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Silhanek AV Ebihara T Harrison N Jaime M Tezuka K Fanelli V Batista CD 《Physical review letters》2006,96(20):206401
We show that antiferromagnetism in lightly (approximately 8%) Sn-doped CeIn3 terminates at a critical field mu0H(c) = 42 +/- 2 T. Electrical transport and thermodynamic measurements reveal the effective mass m* not to diverge, suggesting that cubic CeIn3 is representative of a critical spin-density wave (SDW) scenario, unlike the local quantum critical points reported in anisotropic systems such as CeCu(6-x)Au(x) and YbRh2Si(2-x)Ge(x). The existence of a maximum in m* at a lower field mu0H(x) = 30 +/- 1 T may be interpreted as a field-induced crossover from local moment to SDW behavior as the Néel temperature falls below the Fermi temperature. 相似文献
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A. Yu. Aladyshkin A. S. Mel’nikov D. A. Ryzhov A. V. Samokhvalov A. A. Fraerman W. Gillijns A. V. Silhanek V. V. Moshchalkov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(1):3-7
The results of theoretical and experimental investigations of the peculiarities of the nucleation of superconductivity in the presence of a nonuniform magnetic field induced by ferromagnetic films or dots with out-of-plane magnetic anisotropy are reviewed. It is shown that the phase transition line of superconductor-ferromagnet hybrids in the H-T plane (H is an external magnetic field and T is temperature) is determined significantly by the spatial distribution of nonuniform magnetic field. It allows to control the thermodynamic and transport properties of superconductor-ferromagnet hybrids by tuning the magnetic state of the ferromagnet. 相似文献
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Field polarity dependent nucleation of superconductivity in quasi-one-dimensional magnetic templates
G.W. Ataklti A.V. Silhanek J. Van de Vondel W. Gillijns A. Belkin G. Karapetrov V.V. Moshchalkov 《Physica C: Superconductivity and its Applications》2010,470(19):860-862
We investigate the nucleation of superconductivity in an Al/Al2O3/Py trilayer system by electrical transport measurements. Magnetic force microscopy images taken at room temperature show that the 0.7 μm thick Py-film form stripes of magnetic domains with alternating out-of-plane stray field. After applying a strong out of plane magnetic field H the superconductor/normal phase boundary becomes asymmetric with respect to H = 0. This lack of field polarity symmetry results from the unbalanced size distribution of domains with opposite polarity. 相似文献
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Valev VK Silhanek AV Jeyaram Y Denkova D De Clercq B Petkov V Zheng X Volskiy V Gillijns W Vandenbosch GA Aktsipetrov OA Ameloot M Moshchalkov VV Verbiest T 《Physical review letters》2011,106(22):226803
In high definition mapping of the plasmonic patterns on the surfaces of nanostructures, the diffraction limit of light remains an important obstacle. Here we demonstrate that this diffraction limit can be completely circumvented. We show that upon illuminating nanostructures made of nickel and palladium, the resulting surface-plasmon pattern is imprinted on the structures themselves; the hotspots (regions of local field enhancement) are decorated with overgrowths, allowing for their subsequent imaging with scanning-probe techniques. The resulting resolution of plasmon pattern imaging is correspondingly improved. 相似文献
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R Nirmala V Sankaranarayanan K Sethupathi AV Morozkin T Geethakumary Y Hariharan 《Pramana》2002,58(5-6):1101-1104
New R
2Ti3Ge4 (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac
magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize
in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series.
The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales
with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays
a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects. 相似文献
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Silhanek AV Jaime M Harrison N Fanelli VR Batista CD Amitsuka H Nakatsuji S Balicas L Kim KH Fisk Z Sarrao JL Civale L Mydosh JA 《Physical review letters》2006,96(13):136403
We report measurements and analysis of the specific heat and magnetocaloric effect-induced temperature changes at the phase boundary into the single magnetic field-induced phase (phase II) of U(Ru0.96Rh0.04)2Si2, which yield irreversible properties similar to those at the valence transition of Yb(1-x)Y(x)InCu4. To explain these similarities, we propose a bootstrap mechanism by which lattice parameter changes caused by an electric quadrupolar order parameter within phase II become coupled to the 5f-electron hybridization, giving rise to a valence change at the transition. 相似文献
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A. Leo G. Grimaldi A. Nigro S. Pace N. Verellen A.V. Silhanek W. Gillijns V.V. Moshchalkov V. Metlushko B. Ilic 《Physica C: Superconductivity and its Applications》2010,470(19):904-906
We study the influence of artificial pinning centers on the vortex critical velocity in Al thin films deposited on top of a periodic array of Permalloy (FeNi) square rings. We demonstrate that the field dependence of the flux flow velocity strongly depends on the particular magnetic state of the rings. In particular, we find that, even when the rings are in a flux closure state, i.e. with little stray field, the vortex critical velocity shows a non-monotonic magnetic field dependence. This behaviour is in sharp contrast with the results obtained in a reference plain film, with no rings underneath. A comparison with the intrinsic strong pinning Nb films previously studied, suggests an interpretation in terms of a channel-like motion of vortices, here induced by the artificial pinning structure. 相似文献