Comment on “Origin of the Superconductivity in the Y-Sr-Ru-O and Y-Sr-Cu-O Systems”
Galstyan [Phys. Rev. B 76, 014501 (2007)] asserted that superconductivity reported for Sr2 YRu1-u Cuu O6 is due to inclusions of YSr2 Cu3 O7. We have synthesized samples of this magnetic material (u=0.10) which exhibit diamagnetism exceeding that possible even if all of the available dopant Cu were present in YSr2 Cu3 O7. Our materials were studied with neutron diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and SQUID magnetometry. We found no evidence for inclusions of YSr2 Cu3 O7. Despite their claim, this is in agreement with a primary finding of Galstyan that granular YSr2 Cu3 O7 is present only in material doped with Cu at 250% of the known Cu solubility limit. The lack of superconductivity at low Cu doping in their material is likely due to their failure to follow published synthesis procedures. It is concluded that the findings of Galstyan actually support our contention that properly synthesized Sr2 YRu1-u Cuu O6 is a single phase material which exhibits high temperature superconductivity. © 2009 The American Physical Society.
H. A. Blackstead et al., "Comment on “Origin of the Superconductivity in the Y-Sr-Ru-O and Y-Sr-Cu-O Systems”," Physical Review B - Condensed Matter and Materials Physics, American Physical Society (APS), Jan 2009.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.79.016501
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