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arXiv · 1506.08108

Macroscopic quantum tunneling in spin filter ferromagnetic Josephson junctions

D. Massarotti·A. Pal·G. Rotoli·L. Longobardi·M. G. Blamire·F. Tafuri
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Abstract

The interfacial coupling of two materials with different ordered phases, such as a superconductor (S) and a ferromagnet (F) is driving new fundamental physics and innovative applications. For example, the creation of spin-filter Josephson junctions and the demonstration of triplet supercurrents have suggested the potential of a dissipationless version of spintronics based on unconventional superconductivity. Here we demonstrate evidence for active quantum applications of S-F-S junctions, through the observation of macroscopic quantum tunneling in Josephson junctions with GdN ferromagnetic insulator barriers. We prove a clear transition from thermal to quantum regime at a crossover temperature of about 100 mK at zero magnetic field in junctions which demonstrate a clear signature of unconventional superconductivity. Following previous demonstration of passive S-F-S phase shifters in a phase qubit, our result paves the way to the active use of spin filter Josephson systems in quantum hybrid circuits.

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D. Massarotti, A. Pal, G. Rotoli, L. Longobardi, M. G. Blamire, F. Tafuri. 2015-06-26. Macroscopic quantum tunneling in spin filter ferromagnetic Josephson junctions. https://doi.org/10.1038/ncomms8376

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