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

Abstract

Ceramic high- T c superconductors may be viewed as a weakly coupled random Josephson network containing so-called π-junctions. Kawamura and Li proposed that a novel glassy phase, a chiral-glass phase, might occur in d-wave ceramics. This prediction was supported by experimental results on YBa 2Cu 4O 8 ceramics. In the present work, the pressure dependence of the chiral-glass transition has been investigated by magnetic measurements on the ceramic YBa 2Cu 4O 8. The transition temperature increases linearly with increase in pressure, and the singular behaviors of the susceptibilities are scaled by the transition temperature. The results suggested that the transition occurs in frustrated Josephson network and depends only on the strength of Josephson junctions between grains.