Vortex states in high-Tc superconductors and superconductivity in modern nano-science and engineering

• Published in: Science and technology of advanced materials Vol. 6; no. 6; pp. 589 - 603
• Main Author: Kadowaki, Kazuo
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.09.2005; IOP Publishing
• Subjects: Nano-technology; Super conductivity; Vortex states
• ISSN: 1468-6996; 1878-5514
• DOI: 10.1016/j.stam.2005.07.002

Abstract A brief review is given on the recent development of the vortex engineering research in our group with special emphasis on the geometrical confinement of vortices into micron-size of samples. We show that the static as well as dynamical nature of vortices is strongly affected by the geometrical constraints, which can be manipulated by the recent nano-technology engineering artificially. One of the spectacular phenomena in this context is a formation of self-organized vortex structures occuring both in static and dynamic manners. The static behaviors have been studied by the scanning SQUID microscope technique and the dynamical behaviors are mostly done in transport measurements. Some technical development of these methods is also discussed. We stress that a common generic concept here is the confinement in nano-scale superconducting systems by the existing surfaces (boundaries), which plays an essential role for the phenomena. Some typical examples are shown, such as results on the vortex arrangement in micron size superconducting disks, a formation of the giant vortex state in such a particular case and the dynamical effects of vortices, especially in the case of Josephson vortices confined in an intrinsic Josephson junction in micron size single crystal Bi 2 Sr 2 CaCu 2 O 8+δ , where the dynamical effect of the confinement provides rich linear and non-linear phenomena due to the excitation of Josephson plasma. Making use of Josephson plasma excitations, a generator operating at T (Hz) frequencies is proposed in this intrinsic Josephson junctions. These phenomena are expected to be all beneficial to potential applications.