Structure and oxygen-index relations in some superconducting (RE)Ba2Cu3O7−x compounds. Part I

Abstract

It is shown that along with the oxygen loss in yttrium, gadolinum and erbium compounds, (RE)Ba₂Cu₃O₇, the orthorhombic distortion of the crystal lattice decreases smoothly and disappears at oxygen index values between 6.3 and 6.4. The unit cell volume expansion that accompanies the oxygen loss is due to a rise in the lattice parameter c, which in the range of 6.3 to 7.0 can be used to estimate the oxygen content of the sample.