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Advances in Condensed Matter Physics
Volume 2012 (2012), Article ID 902812, 7 pages
Research Article

Chemical Phase Separation of Superconductive and Ferromagnetic Domains in

Department of Physics, Faculty of Engineering, Yokohama National University, Hodogaya-ku, Yokohama 240-8501, Japan

Received 19 September 2012; Accepted 12 December 2012

Academic Editor: Cong Wang

Copyright © 2012 Takahiro Yamazaki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Various ZnNyNi3−xCox compounds with differing Co content, x, were synthesized, and their magnetic properties were investigated. Uniform solid solutions could not be obtained at low Co content ( ); instead micrometer-scaled ferromagnetic ZnNyNi0.6Co2.4 domains formed embedded within a superconductive ZnNNi3 bulk, showing chemical phase separation of superconductive ZnNNi3 and ferromagnetic ZnNyNi0.6Co2.4. At intermediate levels of Co concentration ( ), this two-phase separation might persist, and the superconductive behavior was strongly suppressed in this composition region. Only at high Co concentration ( ) the uniform ferromagnetic solid solution ZnNyNi3−xCox (with most likely ) formed. The phase separation behavior is intrinsic to the system, reflecting the existence of a miscibility gap in ZnNyNi3−xCox for the samples with , and was shown not to be attributable to incomplete synthesis. In the two-phased samples, high-quality granular contact between the superconductor and ferromagnet has been realized, suggesting that the production of useful devices requiring high-quality contacts between superconductors and ferromagnets may be possible by making use of this two-phase situation.