相关论文: Dissipation in Mesoscopic Superconductors with Ac …
A single vortex overcoming the surface barrier in a mesoscopic superconductor with lateral dimensions of several coherence lengths and thickness of several nanometers provides an ideal platform to study thermal activation of a single…
As superconductors are cooled below their critical temperature, stray magnetic flux can become trapped in regions that remain normal. The presence of trapped flux facilitates dissipation of ac current in a superconductor, leading to losses…
We report results of dc magnetic and ac linear low-frequency study of a polycrystalline MgB$_2$ sample. AC susceptibility measurements at low frequencies, performed under dc fields parallel to the sample surface, provide a clear evidence…
The damping of the oscillations of a small permanent magnet (spherical shape, radius 0.1 mm) levitating between two parallel epitaxial YBCO films is measured as a function of oscillation amplitude and temperature. At small amplitudes the…
The frequency dependence of the equilibrium ac conductance (or the noise power spectrum) through a mesoscopic structure is shown to exhibit steps and dips. The steps, at energies related to the resonances of the structure, are closely…
In this article, we examine the superconducting properties of low- and high-$T_c$ magnetic superconductors in magnetic fields close to the first penetration field. Attention is paid to the properties that relate to the interactions between…
Numerical simulations of the hysteretic ac loss in a coated superconductor with a more realistic version of architecture were performed via finite-element technique in the presence of an oscillating magnetic field. The coated superconductor…
Ta$_{2}$S$_{2}$C compound undergoes superconducting transitions at $T_{cl} = 3.60 \pm 0.02$ K and $T_{cu} = 9.0 \pm 0.2$ K. The nature of successive superconducting transitions has been studied from electrical resistivity, linear and…
The capacitance of mesoscopic samples depends on their geometry and physical properties, described in terms of characteristic times scales. The resulting ac admittance shows sample to sample fluctuations. Their distribution is studied here…
Effects of anisotropic gap structures on a diamagnetic response are investigated in order to demonstrate that the field-angle-resolved magnetization ($M_L(\chi)$) measurement can be used as a spectroscopic method to detect gap structures.…
We exploit magnetostriction in polydisperse ferrofluids in order to generate nonlinear responses, and apply a thermodynamical method to derive the desired nonlinear magnetic susceptibility. For an ideal gas, this method has been…
We study the magnetic interaction between two superconducting concentric mesoscopic Al loops, close to the superconducting/normal phase transition. The phase boundary is measured resistively for the two-loop structure as well as for a…
The interaction between the quantum states of two aluminum superconducting rings forming an 8-shape circular-asymmetric microstructure was examined under a threading magnetic flux and bias by an alternating current without a dc component.…
The phase of Aharonov-Bohm oscillations in mesoscopic metal rings in the presence of a magnetic field can be modulated by application of a DC-bias current I_DC. We address the question of how a variation of I_DC and hence of the microscopic…
We show in the case of a superconducting Nb ladder that a mesoscopic superconductor typically exhibits magnetoresistance oscillations whose amplitude and temperature dependence are different from those stemming from the Little-Parks effect.…
We report measurements of thermopower oscillations $vs$ magnetic field in a diffusive Andreev interferometer. Upon the increase of the dc current applied to the heater electrodes, the amplitude of these oscillations first increases then…
The fluorescence spectra of a sub-micron atomic cesium vapor layer observable under resonant excitation on D2 line have been studied in the presence of an external magnetic field. Substantial changes in amplitudes and frequency positions of…
The normal/superconducting phase boundary Tc has been calculated for mesoscopic loops, as a function of an applied perpendicular magnetic field H. While for thin-wire loops and filled disks the Tc(H) curves are well known, the intermediate…
A theory of dissipative nonlinear conductivity, $\sigma_1(\omega,H)$, of s-wave superconductors under strong electromagnetic fields at low temperatures is proposed. Closed-form expressions for $\sigma_1(H)$ and the surface resistance…
We report results of experimental studies of ac susceptibility of Nb single crystal at low frequencies in swept magnetic fields applied parallel to the surface. Analysis of the experimental data shows that the swept magnetic field…