1. Superconducting Materials LaboratoryGraduate School of Science and EngineeringShibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku Tokyo 135-8548 Japan
2. Institute of Experimental PhysicsSAS Watsonova 47 04001 Košice Slovakia
3. Institute of Physics Na Slovance 2, CZ-18221 Praha 8 Prague Czech Republic