Multiscale distribution of oxygen puddles in 1/8 doped YBa(2)Cu(3)O(6.67)

Despite intensive research a physical explanation of high T(c) superconductors remains elusive. One reason for this is that these materials have generally a very complex structure making useless theoretical models for a homogeneous system. Little is known on the control of the critical temperature by the space disposition of defects because of lack of suitable experimental probes. X-ray diffraction and neutron scattering experiments used to investigate y oxygen dopants in YBa(2)Cu(3)O(6+y) lack of spatial resolution. Here we report the spatial imaging of dopants distribution inhomogeneity in YBa(2)Cu(3)O(6.67) using scanning nano X-ray diffraction. By changing the X-ray beam size from 1 micron to 300 nm of diameter, the lattice inhomogeneity increases. The ordered oxygen puddles size distribution vary between 6–8 nm using 1 × 1 μm(2) beam, while it is between 5–12 nm with a fat tail using the 300 × 300 nm(2) beam. The increased inhomogeneity at the nanoscale points toward a network of superconducting puddles made of ordered oxygen interstitials.