SEMICONDUCTIVITY IN YBA2-XSRXCU3OY

Structural and electrical properties of YBa(2-x)Sr(x)Cu3O(y) prepared under ambient oxygen pressure were systematically investigated for 0 l ess than or equal to x less than or equal to 2.0. Samples with high Sr contents, x greater than or equal to 1.7, showed semiconductive prope rties with an activation energy of similar to 150 meV at high temperat ure, T greater than or equal to 80 K. At low temperatures, T less than or equal to 80 K, activation energy dropped to similar to 3.00 and si milar to 0.85 meV for x=1.7-1.8 and x=1.9-2.0, respectively. It is arg ued that YSr2Cu3Oy is likely to have a tetragonal structure and that t he disorder introduced by Sr substitution affects electrical conductio n, which involves charge hopping between the CuO chains at high Sr con tents. (C) 1996 American Institute of Physics.