High quality ferromagnetic 0 and π Josephson tunnel junctions

Weides, M. , Kemmler, M., Goldobin, E., Koelle, D., Kleiner, R., Kohlstedt, H. and Buzdin, A. (2006) High quality ferromagnetic 0 and π Josephson tunnel junctions. Applied Physics Letters, 89(12), 122511. (doi:10.1063/1.2356104)

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Abstract

The authors fabricated high quality Nb/Al2O3 /Ni0.6Cu0.4 /Nb superconductor-insulatorferromagnet-superconductor Josephson tunnel junctions. Depending on the thickness of the ferromagnetic Ni0.6Cu0.4 layer and on the ambient temperature, the junctions were in the 0 or π ground state. All junctions have homogeneous interfaces showing almost perfect Fraunhofer patterns. The Al2O3 tunnel barrier allows one to achieve rather low damping, which is desired for many experiments especially in the quantum domain. The McCumber parameter c increases exponentially with decreasing temperature and reaches c700 at T= 2.11 K. The critical current density in the π state was up to 5 A/cm2 at T= 2.11 K, resulting in a Josephson penetration depth J as low as 160 μm. Experimentally determined junction parameters are well described by theory taking into account spin-flip scattering in the Ni0.6Cu0.4 layer and different transparencies of the interfaces.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Weides, Professor Martin
Authors: Weides, M., Kemmler, M., Goldobin, E., Koelle, D., Kleiner, R., Kohlstedt, H., and Buzdin, A.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Applied Physics Letters
Publisher:AIP Publishing
ISSN:0003-6951
ISSN (Online):1077-3118
Published Online:19 September 2006

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