High-resolution transmission electron microscopy studies of planar defects in the magnetic superconductor RuSr2EuCu2O8

The defect structure in powders of the 1212-type phase RuSr2EuCu2O8 was investigated using high-resolution transmission electron microscopy. Both 90degrees domain boundaries and planar "faults" on {100} were observed. By comparing images of the faults with simulations for various plausible atomic models, it was shown that they are crystallographic shear planes with a displacement vector of R=(1/6)<332>. Such defects correspond to a local deficiency in Ru, Cu, and O, and give a local discontinuity in the Ru-O charge reservoir planes. As such, these defects may be responsible for the sensitivity of the superconducting and magnetic properties to processing conditions. (C) 2004 American Institute of Physics.