Atomic ordering in the normal and superconducting state characteristics of YBa2Cu3O<i>x</i> HTS oxides
Аннотация
It is shown that when YBa2Cu3Ox ceramic samples with an initial value x = 6.86 are heated to temperatures in the interval 200–450 °C, held under isothermal conditions, and quenched, the ratio of oxygen to vacancy concentration in the CuOx-6 plane changes and this results in the formation of ordered states for x = 6.83, 6.80, 6.75, and 6.67. The ordering can be seen clearly in the dependences P(x) of the superconducting phase volume and σ(x) of room-temperature conductivity. The correlation between these characteristics enables us to substantiate the concepts about the superconducting cluster with a nearly ordered structure and a carrier concentration close to the value corresponding to the filling of an integral number of bands.
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