Single crystal growth of T*-phase SmLa0.8Sr0.2CuO4

A single crystal of SmLa0.8Sr0.2CuO4 superconductor has been grown by means of the travelling solvent floating zone method. The growth was performed i n a 1:20 mixture of oxygen and argon with a total pressure of 2 bar. The hi ghest bulk superconducting transition temperature of 24 K was achieved afte r annealing the as grown crystal in 200 bar oxygen at 600 degreesC for 7 da ys and 300 degreesC for 3 days followed by slow cooling to room temperature . The structural refinement analysis of the XRD pattern for the as-grown an d as-annealed crystal reveals an enlargement of the unit cell in all crysta llographic directions, with the T-type and T'-type block layers indicating respectively c-direction expansion and shrinkage due to the annealing proce ss. This result further shows an increase in oxygen filling at the apical s ite of the T-block, which explains the occurrence of bulk superconductivity in our crystal. (C) 2001 Elsevier Science B.V. All rights reserved.