| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
In the first year, 2000, I have studied two subjects on the vortex states in three-dimensional layered superconductors. First, I have given n theory on a transition to a glass phase of Josephson vortices induced by an applied field parallel to the layers. Recently, this theory has been justified by a couple of domestic sad foreign experimental works. Next, a theory explaining a material dependence of vortex phase diagram in fields perpendicular to the layers was proposed, and, consistently with experimental results on superconducting YBaCuOs, the presence of a lower critical point of the first order transition line was argued.
In 2001 and 2002, our main interests have moved onto quantum superconducting fluctuation effects in vortex states. First, one of my students (H.Ishida) and I have formulated a microscopic theory applicable to the superconductor-insulator transition behavior induced by a magnetic field in amorphous superconducting films with s-wave pairing and have qualitatively explained the corresponding resistive phenomena. Further, this theory was phenomenologically extended to superconducting cuprates and organics of which the microscopic mechanisms are still controversial, and anomalous transport phenomena in the vortex liquid regime of these materials with very low condensation energy were shown to arise from the strong quantum fluctuation effect at finite temperatures.
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