HIGH PRESSURE STUDY ON SOME HIGH-Tc SUPERCONDUCTORS

Abstract

We present a brief review on the pressure effects of some high temperature super-conductors. The examined systems include RBa 2 Cu 3 O 7, (R, Pr)Ba 2 Cu 3 O 7 and (ZnPc) y Bi 2 Sr 2 Ca 2 Cu 3 O 10, with R=rare earth elements and Pc=phthalocyanine. The results of the presssure effects on the superconducting transition temperature T c in these materials have, thus, not only revealed the origin of the T c -variation induced by the chemical substitution or intercalation, but have also confirmed the important roles played by the carrier concentration and T co (maximum T c ) on determining T c . Based on our experimental results, along with good agreement between our data and theory, we have clearly demonstrated that the variation of T c dominantly originates from the strains induced by the variation of the ionic radii or the intercalation of foreign molecules.