North-Holland PHYSICA Pressure dependence of Tc and Hc2 of CaLaBaCu307 up to 50 GPa

At 01n Tc/Op = 1.5 × 10- 3 GPa- 1, the relative change of the superconducting critical temperature T ¢ with pressure p in CaLa-BaCu307 is found to be smaller than in any other high-To compound. Even more remarkable isthat this low value applies to the whole range from 0 to 50 GPa (with is the highest pressure ver reached in the investigation of Tc for any compound), Using measurements of the upper critical field H¢2 ( T, p) to 40 GPa, we deduce that ( 1) the charge carrier concentration is virtually unaffected by pressure, in striking contrast with e.g. YBa2Cu4Os and (2) that he net effect on Tc of the pressure induced changes of all other parameters is extremely small. 1