Various regimes of flux motion in Bi2Sr2CaCu2O8+δ single crystals
نویسنده
چکیده
Four regimes of vortex motion were identified in the magnetoresistance of Bi2Sr2CaCu2O8+δ single crystals: (1) thermally activated flux flow (TAFF) in samples with surface defects caused by thermal annealing; (2) TAFF-like plastic motion of highly entangled vortex liquid at low temperatures, with Upl ∼ (1− T/Tc)/H ; (3) pure free flux flow above the region of (2) in clean and optimally doped samples; or, in its place, (4) a combination of (2) and (3). This analysis gives an overall picture of flux motion in Bi cuprates.
منابع مشابه
Pressure Dependence of Flux Dynamics in Bi2Sr2CaCu2O8+δ
An important problem in high temperature superconductivity is that of understanding, and ultimately controlling, fluxoid motion. Results are presented in this paper which were obtained using a new technique for measuring the pressure dependence of the transition to superconductivity in a diamond-anvil cell. By monitoring the third harmonic of the acsusceptibility, we observe the onset of irreve...
متن کاملar X iv : c on d - m at / 9 41 00 65 v 1 1 8 O ct 1 99 4 The Pairing Mechanism in HTSC investigated by Electronic Raman Scattering
By means of electronic Raman scattering we investigated the symmetry of the energy gap 2∆(~k), its temperature dependence and its variation with doping of well characterized Bi2Sr2CaCu2O8+δ single crystals. The oxygen content δ was varied between the underand the overdoped regime by subsequently annealing the same single crystal in Ar and in O2, respectively. The symmetry analysis of the polari...
متن کاملSymmetry of the superconducting gap in HgBa2CaCu2O6+δ single crystals from electronic Raman scattering
Pure electronic Raman spectra with no phonon structures superimposed on the low energy electronic continuum, are reported for the first time, in optimally doped HgBa2CaCu2O6+δ single crystals (Tc = 126 K). Our low temperature spectra (15 K) for the A1g, B1g and B2g symmetries exhibit striking differences with previous data in Bi2Sr2CaCu2O8+δ . The shape of the spectra for the various symmetries...
متن کاملMicrowave-induced constant voltage steps in surface junctions of Bi2Sr2CaCu2O8+δ single crystals
We have observed the zero-crossing steps in a surface junction of a mesa structure micro-fabricated on the surface of a Bi2Sr2CaCu2O8+δ single crystal. With the application of microwave of frequencies 76 and 94 GHz, the currentvoltage characteristics show clear voltage steps satisfying the ac Josephson relation. Increasing the microwave power, the heights of the steps show the Bessel-function b...
متن کاملVortex liquid correlations induced by in-plane field in underdoped Bi2Sr2CaCu2O8+δ
By measuring the Josephson Plasma Resonance, we have probed the influence of an in-plane magnetic field on the pancake vortex correlations along the c-axis in heavily underdoped Bi2Sr2CaCu2O8+δ (Tc = 72.4 ± 0.6 K) single crystals both in the vortex liquid and in the vortex solid phase. Whereas the in-plane field enhances the interlayer phase coherence in the liquid state close to the melting li...
متن کامل