Suppressed Superconductivity of the Surface Conduction Layer in Bi2_2Sr2_2CaCu2_2O8+x_{8+x} Single Crystals Probed by {\it c}-Axis Tunneling Measurements

We fabricated small-size stacks on the surface of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ (BSCCO-2212) single crystals with the bulk transition temperature $T_c$$\simeq$90 K, each containing a few intrinsic Josephson junctions. Below a critical temperature $T_c'$ ($\ll$ $T_c$), we have observed a weakened Josephson coupling between the CuO$_2$ superconducting double layer at the crystal surface and the adjacent one located deeper inside a stack. The quasiparticle branch in the $IV$ data of the weakened Josephson junction (WJJ) fits well to the tunneling characteristics of a d-wave superconductor($'$)/insulator/d-wave superconductor (D$'$ID) junction. Also, the tunneling resistance in the range $T_c'$$<$$T$$<$$T_c$ agrees well with the tunneling in a normal metal/insulator/d-wave superconductor (NID) junction. In spite of the suppressed superconductivity at the surface layer the symmetry of the order parameter appears to remain unaffected.Comment: 13 pages, 6 figure

Service Systems and Service Innovation: Toward the Theory of Service Systems

Services have been regarded as something intangible, perishable, and heterogeneous so that it is difficult to measure the quality and productivity of them. Services also have long been considered non-productive economic activities. However, considering the recent growth of service industry across the world, it is imperative to study the very nature of service and its systems in the knowledge-based economy from an integrated perspective to improve the quality of life and effective economic development. For this, we in this study will develop a systematic way of understanding the nature service in the knowledge-based economy from a systems’ perspective and build an integrated theory of service systems which facilitates service innovation and improves service productivity. The proposed theory will provide the foundation for designing, producing, delivering, operating, maintaining, monitoring, and improving service systems, which in turn leads to service innovation and thus a sustainable economic growth with providing greater employment opportunities. This study will also provide researchers and companies with the basis for future study and guidelines to further service innovation