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We study the magnetic instability of gapless superconductors. The instability arises due to the infrared divergence associated with the gapless modes of the superconductor. When the Fermi-surface mismatch between pairing fermions is close…

High Energy Physics - Phenomenology · Physics 2007-05-23 Deog Ki Hong

We report measurements of magnetic switching and steady-state magnetic precession driven by spin-polarized currents in nanoscale magnetic tunnel junctions with low-resistance, < 5 Ohm-micron-squared, barriers. The current densities required…

We observe magnetization dynamics induced by spin momentum transfer in the noise spectra of current perpendicular to the plane giant magnetoresistance spin valves. The dynamics are observable only for those combinations of current direction…

Materials Science · Physics 2009-11-10 M. Covington , M. AlHajDarwish , Y. Ding , N. J. Gokemeijer , M. A. Seigler

The Josephson plasma resonance in layered superconductors with alternating critical current densities is investigated in a low perpendicular magnetic field. In the vortex solid phase the current densities and the squared bare plasma…

Superconductivity · Physics 2009-11-07 L. N. Bulaevskii , Ch. Helm

In strongly compressible magnetohydrodynamic turbulence, obliqueness between the large-scale density gradient and magnetic field gives an electromotive force mediated by density variance (intensity of density fluctuation). This effect is…

Solar and Stellar Astrophysics · Physics 2022-05-31 Nobumitsu Yokoi , Steven M. Tobias

High frequency oscillations are observed in a neon plasma of a direct current magnetron discharge. At low discharge currents, we see highly coherent 60 MHz fluctuations. Above a distinct current threshold, secondary 5 - 10 MHz fluctuations…

Plasma Physics · Physics 2024-05-07 Ryan C. Przybocki , Mark A. Cappelli

The dynamics of the oscillator system is investigated. The conditions under which this dynamics becomes unstable are determined. In particular, it is shown that plasma in constant magnetic field becomes unstable if its density exceeds a…

Plasma Physics · Physics 2019-04-23 Vyacheslav Buts

Current sheets formed in magnetic reconnection events are found to be unstable to high-wavenumber perturbations. The instability is very fast: its maximum growth rate scales as S^{1/4} v_A/L, where L is the length of the sheet, v_A the…

Astrophysics · Physics 2009-11-13 N. F. Loureiro , A. A. Schekochihin , S. C. Cowley

We study a diffusive superconductor - normal metal - superconductor (SNS) junction in an external magnetic field. In the limit of a long junction, we find that the form of the dependence of the Josephson current on the field and on the…

Superconductivity · Physics 2013-04-16 B. Crouzy , D. A. Ivanov

We investigate energy transfer and localization in a linear time-invariant oscillator chain weakly coupled to a forced nonlinear actuator. Two types of perturbation are studied: (1) harmonic forcing with a constant frequency is applied to…

Pattern Formation and Solitons · Physics 2015-01-06 Agnessa Kovaleva

The artificial magnetic fields engineered for ultra cold gases depend on the internal structure of the neutral atoms. Therefore the components of a mixture composed of two atomic gases can exhibit a different response to an artificial…

Quantum Gases · Physics 2019-07-02 S. Seyyare Aksu , A. Levent Subaşı , Nader Ghazanfari

The critical currents in Josephson junctions of conventional superconductors with macroscopic defects are calculated for different defect critical current densities as a function of the magnetic field. We also study the evolution of the…

Superconductivity · Physics 2009-10-31 N. Stefanakis , N. Flytzanis

The dynamics of a single spin embedded in a the tunnel junction between ferromagnetic contacts is strongly affected by the exchange coupling to the tunneling electrons. Moment reversal of the local spin induced by the bias voltage across…

Mesoscale and Nanoscale Physics · Physics 2008-06-04 J. Fransson

For atoms described by a 1-dimensional Friedrichs model we present the following result: pre-existing resonances, when subjected to a small constant electric field (DC Stark effect), are unstable in the weak field limit. In contrast,…

Quantum Physics · Physics 2014-04-01 I. Herbst , J. Rama

Semiconductor $p^+ - p^- - n - p^+ - n^{++}$ structures with large junction and contact areas are treated as 1 \times 2-dimensional active media, in which self-organized pattern formation can be expected. The local bistable behavior of the…

patt-sol · Physics 2009-10-31 A. V. Gorbatyuk , F. -J. Niedernostheide

The mode dependence of current-induced magnetic excitations in spin valves is studied theoretically. The torque exerted on the magnetization by transverse spin currents as well as the Gilbert damping constant are found to depend strongly on…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Arne Brataas , Yaroslav Tserkovnyak , Gerrit E. W. Bauer

Persistent current in one-dimensional non-superconducting mesoscopic rings threaded by a slowly varying magnetic flux $\phi$ is studied based on the tight-binding model. The behavior of the persistent current is discussed in three aspects:…

Mesoscale and Nanoscale Physics · Physics 2009-05-20 Santanu K. Maiti

We investigate the dependence of the switching current density on the exchange stiffness constant in the spin transfer torque magnetic tunneling junction structure with micromagnetic simulations. Since the widely accepted analytic…

Materials Science · Physics 2015-06-05 Chun-Yeol You

It is shown that the electric current of massive fermions along the external magnetic field can be excited in the case when particles possess anomalous magnetic moments and electroweakly interact with background matter. This current is…

High Energy Physics - Phenomenology · Physics 2018-02-15 Maxim Dvornikov

The electromagnetic modes possibly unstable in strongly magnetized plasmas are identified. The regime where this instability might stand out compared to the incoherent electron-cyclotron radiation is explored. These modes are relevant to…

Plasma Physics · Physics 2012-11-06 S. Son , Sung Joon Moon