No abstract

High-pressure study has played an important role in the investigation of conventional superconductors. Since the discovery of cuprate superconductors, high-pressure study has become even more important, especially as regards high-pressure synthesis and the effect of pressure. In this report, the new materials Ca-doped Pr-123, (Fe, Cu)-1212, and MgB2—a very new and interesting system synthesized under high pressure with good quality—will be discussed. Chemical inner pressure has been thought to explain the high Tc of Ca-doped Pr-123. As another possibility, the replacement of the physical pressure effect by a chemical effect will be discussed.