Fluctuation, ‘melting”, depinning, creep, and diffusion of the flux-line lattice in high-Tc superconductors

Resistivity, fluctuation‐enhanced conductivity, and irreversibility line of high‐quality Tl2Ba2Ca2Cu3O10 single crystals

“…All crystals show nearly the same behaviour with an exponential dependence of T, on the applied field in the large field range 2 10 -2 T < B < 10 T. The fact that all the T1-2223 crystals show nearly the same T,(B) dependence strongly supports the assumption that the irreversibility is caused by an intrinsic pinning mechanism. In the model of thermally assisted flux flow the diffusion coefficient is given by with the flux-flow resistivity pFF = pn ( T ) B/B,,(T) [29]. Since the main contribution to the temperature dependence of the diffusion coefficient is dominated by the exponential term, the activation energy U for a given field can be obtained from the slope of the Arrhenius plot in Fig.…”

Scanning ESR-microprobe studies of the flux distribution in type-II superconductors

“…These features provide the low pinning energies and cause the pronounced fluctuations of the vortex lattice. This leads to rather unusual properties of the irreversibility line (IL) in the phase diagram of the flux lattice [4][5][6][7][8]. The elucidation of the origin of the irreversibility which manifests itself in the flux distribution seems to be a problem which is highly important for the possible practical use of high-Tc materials.…”

Origin of the irreversibility line in thinYBa2Cu3OProzorov1, Kończykowski2, Schmidt3 et al. 1996Phys. Rev. B20060View full textAdd to dashboardCite

“…Experimentally, this line is defined as the border line at which the magnetic response of the sample changes from irreversible to reversible. In HTS, large fluctuations and relatively weak pinning lead to a rich H − T phase diagram with a variety of dynamic and static transitions which can be responsible for the appearance of magnetic reversibility [3][4][5][10][11][12].…”

“…The origin of the irreversibility line (IRL) in the field-temperature (H −T ) phase diagram of high-temperature superconductors (HTS) is intriguing and still a widely discussed topic [1][2][3][4][5][6][7][8][9]. Experimentally, this line is defined as the border line at which the magnetic response of the sample changes from irreversible to reversible.…”

“…Several models, like thermally activated depinning [2,3,6,13,14], vortex-lattice melting [15][16][17][18][19][20][21] and a transition from vortex glass to vortex fluid [23][24][25], were proposed to identify the origin of the IRL in HTS. Also, attention was given to the possibility of pinning in the vortex-liquid phase [5,10,11,26] and to different dissipation mechanisms above the melting line [5,13,[27][28][29].…”