Zobrazeno 1 - 10
of 358
pro vyhledávání: '"J. Joffrin"'
Publikováno v:
physica status solidi (c). 1:2795-2798
At temperatures below about 30 mK in Si:B the phase relaxation time T2 of the two-level systems associated with the acceptor ground state can be determined from the decay of the two-pulse echo. It has been shown to depend on the concentration of inte
Publikováno v:
Physica B: Condensed Matter. :125-128
Phonon echoes, sound amplification, and acoustic solitons are observed in Si:B at temperatures below about 25 mK depending on the density of states of two-level systems associated with the acceptor ground state. We report on the influence of acceptor
Publikováno v:
Solid State Communications. 110:115-119
We report electrical transport measurements of thin YBCO-films with three different oxygen contents in the mixed state, with a magnetic field applied perpendicular to the CuO2 layers. We have analysed our resistivity data in the framework of two mode
Publikováno v:
Acta Physica Polonica A. 94:487-491
The elastic constants of single crystals of β-ΗgS highly g Y s g g Y with p iron were directly determined at room temperature from the measurements of ultrasonic wave velocities by the pulse-echo technique. The values of c11 = 6.750, c12 = 5.186, a
Publikováno v:
The European Physical Journal B. 2:177-182
We present measurements of the attenuation and phase velocity of surface acoustic waves in thin YBa2Cu3O YBa2Cu3O7‒δ films as a function of temperature, in magnetic fields up to 3.6 T applied parallel to the c-axis of the films. We have observed a
Publikováno v:
Journal of Low Temperature Physics. 105:1313-1318
Comparative studies of a standard four-contact DC method and a contactless mutual inductance setup have been carried out on the temperature dependence of the critical current of YBa2Cu3O7−δ (YBCO) thin films. The DC measurements are restricted to
Autor:
J.-Y. Prieur, M. Stenger, J. Joffrin, T. Königs, G. Ockenfuß, Roger Wördenweber, M. Reese, C. Barre
Publikováno v:
Solid State Communications. 98:777-780
In order to change the oxygen content of YBa 2 Cu 3 O 7−δ thin films, we have measured the YBCO c-axis length “in situ” by X-ray analysis while heating the films in a flow of 10 mbar of molecular oxygen. We observed two kinds of c-axis length
Publikováno v:
Physica B: Condensed Matter. :235-238
We discuss different possibilities to amplify an ultrasonic wave in a glass by inverting the populations of the two-level systems: we show that the only convenient one is the so-called “rapid adiabatic passage”. We describe different steps of the
Publikováno v:
Europhysics Letters (EPL). 24:409-414
Glassy systems have long been known to strongly attenuate ultrasonic waves at low temperatures. This is due to the resonant absorption of phonons by the so-called Two-Level Systems any amorphous medium contains. Should the populations of those TLS be
Publikováno v:
Physical Review B. 48:6604-6611
It has recently been shown that the low temperature acoustic properties of HTC superconductors in the presence of a strong magnetic field can give information on the thermally activated depinning of the vortex lattice [1].