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Quantum interference phenomena in the conductivity of mesoscopic ferromagnets are considered, particularly with regard to the effects of geometric phases acquired by electrons propagating through regions of spatially varying magnetization…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Yuli Lyanda-Geller , I. L. Aleiner , Paul M. Goldbart

The dependence of mesoscopic conductance fluctuations on parallel magnetic field is used as a probe of spin degeneracy in open GaAs quantum dots. The variance of fluctuations at high parallel field is reduced from the low-field variance…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 J. A. Folk , S. R. Patel , K. M. Birnbaum , C. M. Marcus , C. I. Duruoz , J. S. Harris

Electronic phase coherence in normal metals is incredibly sensitive to magnetic scattering. As a result, the weak localization magnetoresistance and time-dependent universal conductance fluctuations are powerful probes of magnetic…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Trionfi , S. Lee , D. Natelson

Temperature dependent weak localization is measured in metallic nanowires in a previously unexplored size regime down to width $w=5$ nm. The dephasing time, $\tau_{\phi}$, shows a low temperature $T$ dependence close to quasi-1D theoretical…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 D. Natelson , R. L. Willett , K. W. West , L. N. Pfeiffer

We consider an s-wave superconductor in the vicinity of a second-order ferromagnetic (FM) or spin-density-wave (SDW) quantum critical point (QCP), where the superconductivity and magnetism arise from separate mechanisms. The quantum…

Superconductivity · Physics 2007-05-23 Y. L. Loh , P. B. Littlewood

The frequency flicker of an oscillator, which appears as a 1/f^3 line in the phase noise spectral density, and as a floor on the Allan variance plot, originates from two basic phenomena, namely: (1) the 1/f phase noise turned into 1/f…

Instrumentation and Detectors · Physics 2009-01-08 Enrico Rubiola , Vincent Giordano

We have studied the force in mesoscopic wires in the presence of an external magnetic field along the wire using a free electron model. We show that the applied magnetic field can be used to affect the force in the wire. The magnetic field…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Sara Blom

The universal conductance fluctuations of quasi-two-dimensional systems are analyzed with experimental considerations in mind. The traditional statistical metrics of these fluctuations (such as variance) are shown to have large statistical…

Mesoscale and Nanoscale Physics · Physics 2012-11-16 M. B. Lundeberg , J. Renard , J. A. Folk

Universal conductance fluctuations in disordered systems are one of the most known quantum mesoscopic effects. For ballistic cavity with smooth confining potential however, one should observe a much larger classical sample-to-sample…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 P. G. Silvestrov

We first argue that the collective behaviour of the Cooper pairs created by thermal fluctuations well above the superconducting transition temperature, Tc, is dominated by the uncertainty principle which, in particular, leads to a…

We have calculated the temperature dependence of the conductance variation ($\delta S(T)$) of mesoscopic superconductor normal metal(S/N) structures, in the diffusive regime, analysing both weak and strong proximity effects. We show that in…

Superconductivity · Physics 2009-10-31 R. Seviour , C. J. Lambert , A. F. Volkov

The mechanism of unconventional superconductivity, such as high-temperature-cuprate, Fe-based, and heavy-fermion superconductors, has been studied as a central issue in condensed-matter physics. Spin fluctuations, instead of phonons, are…

Superconductivity · Physics 2021-10-27 K. Ishida , S. Matsuzaki , M. Manago , T. Hattori , S. Kitagawa , M. Hirata , T. Sasaki , D. Aoki

We have investigated the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au and CoFe thicknesses. Without the CoFe layer the superconducting critical temperatures of Nb/Au bilayers as a function of Au…

Superconductivity · Physics 2009-11-11 Jinho Kim , Yong-Joo Doh , K. Char , Hyeonjin Doh , Han-Yong Choi

We study conductance fluctuations in random resistor networks with hyperuniform bond disorder, where the fluctuations of the number of bonds present in a test volume $V$ scale as $V^{-a}$ with $a > 1/2$. Since small changes in the…

Statistical Mechanics · Physics 2026-05-21 Bikram Pal

We study mesoscopic fluctuations in the supercurrent of a Josephson junction consisting of a topological insulator microbridge between two conventional superconductors. In the model, we account for the strong proximity effect when…

Mesoscale and Nanoscale Physics · Physics 2022-12-02 Marcus Marinho , Guilherme Vieira , Tobias Micklitz , Georg Schwiete , Alex Levchenko

Rings are a model system for studying phase coherence in one dimension. Superconducting rings have states with uniform phase windings that are integer multiples of 2$\pi$ called fluxoid states. When the energy difference between these…

Superconductivity · Physics 2012-07-06 Julie A. Bert , Nicholas C. Koshnick , Hendrik Bluhm , Kathryn A. Moler

We consider the temperature dependence of the sound attenuation and sound velocity in layered impure metals due to superconducting fluctuations of the order parameter above the critical temperature. We obtain the dependence on material…

Superconductivity · Physics 2009-11-10 M. S. Mar'enko , C. Bourbonnais , A. -M. S. Tremblay

We report that low frequency (up to 200 kHz) noise spectra of magnetic tunnel junctions with areas ~10^{-10}cm^2$ at 10 Kelvin deviate significantly from the typical 1/f behavior found in large area junctions at room temperature. In most…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 B. Zhong , Y. Chen , S. Garzon , T. M. Crawford , R. A. Webb

We study the supercurrent in quasi-one-dimensional Josephson junctions with a weak link involving magnetism, either via magnetic impurities or via ferromagnetism. In the case of weak links longer than {\color{black}the magnetic…

Mesoscale and Nanoscale Physics · Physics 2018-12-24 P. A. Ioselevich , P. M. Ostrovsky , Ya. V. Fominov

Critical fluctuations play a fundamental role in determining the spin orders for low-dimensional quantum materials, especially for recently discovered two-dimensional (2D) magnets. Here we employ the quantum decoherence imaging technique…

Mesoscale and Nanoscale Physics · Physics 2024-07-02 Yuxin Li , Zhe Ding , Chen Wang , Haoyu Sun , Zhousheng Chen , Pengfei Wang , Ya Wang , Ming Gong , Hualing Zeng , Fazhan Shi , Jiangfeng Du