THERMAL EXPANSION COEFFICIENT OF SINGLE PHASE SUPERCONDUCTOR YBa₂Cu₃O_7-δ

The thermal expansion coefficient of single phase superconductor YBa₂Cu₃O_7-δ was measured by the method of differential parallel-plate capacitance. An obvious decrease of volume near 205K and a small jump of the thermal expansion coefficient at T_c were observed. The pressure effect was also estimated.