Pressure dependence of chiral-glass transition in Y–Ba–Cu–O ceramics

Abstract Ceramic high- T C superconductors may be viewed as a weakly coupled random Josephson network containing the so-called π-junctions, and a chiral-glass transition is predicted to be occurred in such d-wave ceramics. In the present work, pressure dependence of the chiral-glass transition have been investigated on YBa 2 Cu 3 O 7− y and YBa 2 Cu 4 O 8 ceramics. With decreasing temperature, a superconducting order occurs at first inside each grain at T C1 and furthermore among the grains at T C2 ( T C1 ). The T C2 increases with increase of pressure, while the sharpness of the transition at T C2 does not change. In spite of differences in not only T C2 ’s but also T C1 ’s, the increasing rates of T C2 by pressure are nearly the same.