Towards higher-Tc superconductors

New superconductors discovered in the Akimitsu laboratory are reviewed here. These materials can be categorized into two groups: 1) Cu-oxide superconductors. 1-1 Cu-oxide system having CuO2 planes. 1-2 Ladder lattice superconductor. 2) Exploration of new metal-based superconductors. 2-1 MgB2 and its application. 2-2 Y2C3. 2-3 Carrier-doped wide-gap semiconductors. 2-4 New superconductor with a cage-type structure: R5T6Sn18 (R = Sc, Y, Lu; T = Rh, Ir). Finally, all of the new superconductors discovered in our laboratory are summarized. The outlook for the high-T-c superconductors and our present work are also described.