TILTING OF THE CUO6 OCTAHEDRA IN LA1.83-XEU0.17SRXCUO4 AS SEEN BY EU-151 MOSSBAUER-SPECTROSCOPY

Eu-151 Mossbauer studies of La1.83-xEu0.17SrxCuO4 for 0 less than or e qual to x less than or equal to 0.26 exhibit a quadrupole interaction at the Eu site whose magnitude eQV(zz) strongly depends on both the Sr content x and the temperature T. For a fixed temperature, a Linear re lationship is obtained between the quadrupole interaction and the aver aged CuO6 octahedra tilting angle determined from diffraction studies. The unusually large temperature dependence of eQV(zz) strongly indica tes a temperature dependence of the local structure. In contrast to re cent studies of the local structure La2CuO4-type superconductors by me ans of x-ray-absorption and neutron-scattering techniques, our data gi ve strong evidence that the local octahedra tilting in La1.83-xEu0.17S rxCuO4 corresponds well to the average tilting obtained by diffraction techniques.