HIGH-PRESSURE STUDY ON SOME HIGH-T-C SUPERCONDUCTORS

We present a brief review on the pressure effects of some high tempera ture superconductors. The examined systems include RBa(2)Cu(3)O(7), (R ,Pr)Ba2Cu3O7 and (ZnPc)(y)Bi2Sr2Ca2Cu3O10, with R = rare earth element s and Pc = phthalocyanine. The results of the presssure effects on the superconducting transition temperature T-c in these materials have, t hus, not only revealed the origin of the T-c-variation induced by the chemical substitution or intercalation, but have also confirmed the im portant roles played by the carrier concentration and T-co (maximum T- c) on determining T-c. Based on our experimental results, along with g ood agreement between our data and theory, we have clearly demonstrate d that the variation of T-c dominantly originates from the strains ind uced by the variation of the ionic radii or the intercalation of forei gn molecules.