Orthorhombic crystal structure and oxygen deficient cluster distribution model for YBaCuAlO superconductor.

Single crystal x-ray diffraction measurements on both as-grown as well as oxygenated single crystals of an aluminium doped high temperature superconductor YBaCuAlO revealed the crystal structure to be orthorhombic with space group Pmmm, in contrast to, tetragonal crystal structures corresponding to space group P4/mmm, previously reported for as-grown YBaCuAlO, and conflicting structures on oxygenated YBaCuAlO. The orthorhombic crystal structure was confirmed by powder x-ray diffraction that showed the presence of two peaks corresponding to (020) and (200) reflections associated with orthorhombic structures of space group Pmmm, instead of a single (200) reflection corresponding to tetragonal crystal structures with space group P4/mmm. All the as-grown crystals were found to be superconducting.