Europhys. Lett.
Volume 76, Number 2, October 2006
Page(s) 271 - 277
Section Condensed matter: structural, mechanical and thermal properties
Published online 13 September 2006
Europhys. Lett., 76 (2), pp. 271-277 (2006)
DOI: 10.1209/epl/i2006-10258-6

Experimental study of positionally disordered Josephson junction arrays

Young-Je Yun, In-Cheol Baek and Mu-Yong Choi

Department of Physics and Institute of Basic Science, Sungkyunkwan University Suwon 440-746, Republic of Korea

received 30 March 2006; accepted 24 August 2006
published online 13 September 2006

We experimentally studied the effect of positional disorder on a Josephson junction array. This system provides an experimental realization of a two-dimensional XY model with random phase shifts. Contrary to many earlier numerical and analytical investigations, the results demonstrate that finite-temperature superconductivity is never eliminated by positional disorder. As disorder strength increased, the Kosterltz-Thouless (KT) type low-temperature order changed to a non-KT-type order with long-range phase coherence, persisting even during the maximal disorder limit. A possible finite-temperature glass transition is discussed.

64.60.Cn - Order-disorder transformations; statistical mechanics of model systems.
75.50.Lk - Spin glasses and other random magnets.
74.25.Qt - Vortex lattices, flux pinning, flux creep.

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