Electron Diffraction and Microscopy of the Structures of La-Ba(Sr)-Cu Oxides at Liquid Helium Temperature

Abstract
Structural observation of the oxides, La1.9Ba0.1CuO4 (orthorhombic, T c1.8Sr0.2CuO4 (tetragonal, T c=30 K: zero resistance), was made at liquid helium temperature by means of electron diffraction and microscopy, and the results were compared with those at room temperature. For the both oxides, no differences have been found in the crystal structure and morphology between 4.2 K and room temperature, although the lattice parameters changed as a result of thermal contraction.