X-ray scattering study of the temperature dependence of the structure of the high T_c superconductor La_1.8Sr_0.2CuO₄

We present data from powder scans of the High Tc (≈40 K) superconductor La1.8Sr0.2CuO4 as a function of temperature from room temperature to 10 K. We observe a K2NiF4-type structure, with no evidence for a structural phase transition or anomalous changes in the lattice constants. For T ≳ 190 K we find αa (1/a)da/dT and αc (1/c)dc/dT to be 1.4 ± 0.5 × 10-5K-1 and 1.7 ± 0.5 × 10-5K-1, respectively. © 1987.