TEMPERATURE RELAXATION OF SUPERCONDUCTING TRANSITION OF REBA1.5SR0.5CU3OX (RE=Y, GD) UNDER PRESSURE

Magnetic measurements of the influence of pressure of 1 GPa on superco nducting ReBa1,5Sr0,5Cu3Ox ceramics (Re = Y, Gd) are made. It is shown that the relaxation of T-c is caused by the pressure-induced reorderi ng of oxygen ions in the CuO chains. The relaxation times of T-c under pressure are determined. The effects connected with the changes of su blattice volume and oxygen ions ordering under pressure are differenti ated: The effects are found to depend on oxygen content. The effect ca used by the oxygen ordering increases sharply with decreasing x. To ou r knowledge, the total effect, dT(c)/dP approximate to 20 K . Gpa(-1) for YBa1.5Sr0.5Cu3O6.56 is the highest one for 123 structure HTSCs.