TY - JOUR
T1 - Current noise in HTC polycrystalline superconductors
T2 - A comparison between experiments and different types of percolation models
AU - Cattaneo, L.
AU - Celasco, M.
AU - Masoero, A.
AU - Mazzetti, P.
AU - Puica, I.
AU - Stepanescu, A.
PY - 1996/8/10
Y1 - 1996/8/10
N2 - Experimental results concerning current noise in ceramic high-Tc superconductors under different conditions of temperature and magnetic field are reported and compared with the results of different models based on percolation theory. It is assumed that under a magnetic field the specimens undergo a first stage transition where the grains become superconducting while the weak links are resistive. Further lowering of the temperature gradually increases the number of weak links that become superconducting, until a percolation threshold is reached which gives rise to macroscopic superconductivity. Two noise-generation models based on a switching model recently proposed by Kiss and Svedlindh, where a small number of weak links near a critical state undergo dynamic transitions from the normal to the superconducting state, are numerically developed and discussed. These models seem to give a much better account of the behavior of the noise intensity than a classical model, where the resistance of the weak links fluctuates. Comparison with the experiments is also given.
AB - Experimental results concerning current noise in ceramic high-Tc superconductors under different conditions of temperature and magnetic field are reported and compared with the results of different models based on percolation theory. It is assumed that under a magnetic field the specimens undergo a first stage transition where the grains become superconducting while the weak links are resistive. Further lowering of the temperature gradually increases the number of weak links that become superconducting, until a percolation threshold is reached which gives rise to macroscopic superconductivity. Two noise-generation models based on a switching model recently proposed by Kiss and Svedlindh, where a small number of weak links near a critical state undergo dynamic transitions from the normal to the superconducting state, are numerically developed and discussed. These models seem to give a much better account of the behavior of the noise intensity than a classical model, where the resistance of the weak links fluctuates. Comparison with the experiments is also given.
KW - Electrical resistivity
KW - Fluctuation effects
KW - Type-II superconductors
UR - http://www.scopus.com/inward/record.url?scp=0030212741&partnerID=8YFLogxK
U2 - 10.1016/0921-4534(96)00322-X
DO - 10.1016/0921-4534(96)00322-X
M3 - Article
SN - 0921-4534
VL - 267
SP - 127
EP - 146
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - 1-2
ER -