Investigation of Y sub 1 Ba sub 2 Cu sub 3 O sub 6.9 and Er sub 1 Ba sub 2 Cu sub 3 O sub 6.8 During Cyclic Temperature Variations

Gravimetric investigations of the superconductive ceramics Y sub 1 Ba sub 2 Cu sub 3 O sub 6.9 , Y sub 1 Ba sub 2 Cu sub 2.7 Al sub 0.3 O sub 7.1 and Er sub 1 Ba sub 2 Cu sub 3 O sub 6.8 during cycling heating < - > cooling in the interval 293-1323K at partial pressure of the oxygen 0.02 and 0.2 x 10 exp 5 Nm exp --2 are presented. Intervals of intense weight changes during heating and cooling are determined. Oxygen loss was shown to be the main reason for the weight changes. Structural characteristics and resistivity of the yttrium ceramics in the above-mentioned temperature interval are investigated. Experimental data are discussed within the framework of the models of the quasi-equilibrium and essentially nonequilibrium processes. Binding energy and diffusional parameters of the evolving gas are estimated. Graphs, Photomicrographs. 12 ref.--AA