Session H1: Charge and Spin Transport in Josephson and Proximity Devices
8:00 AM–11:00 AM, Tuesday, March 16, 2010
Room: Oregon Ballroom 201
Sponsoring Unit:
DCMP
Chair: James Sauls, Northwestern University
Abstract ID: BAPS.2010.MAR.H1.1
Abstract: H1.00001 : Non-sinusoidal current-phase relations in SFS pi-Josephson junctions
8:00 AM–8:36 AM
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Author:
Dale J. Van Harlingen
(University of Illinois at Urbana-Champaign)
We report the direct observation of a sin(2$\phi )$ component in the current-phase relation (CPR) of Superconductor-Ferromagnet-Superconductor (SFS) Josephson junctions. The deviation from a sinusoidal CPR is most evident near the crossover between the 0-junction to $\pi $-junction states reached by tuning the thickness of the ferromagnet barrier and the temperature. We measure the CPR in Nb-CuNi-Nb junctions using a phase-sensitive Josephson interferometer technique in which the junctions are incorporated into a superconducting loop coupled to a dc SQUID. We correlate the CPR data with measurements of subharmonic Shapiro steps and anomalous critical current diffraction patterns that have previously been cited as evidence for higher-order Josephson tunneling components. We will discuss possible origins and implications for the non-sinusoidal component. In collaboration with M.J.A. Stoutimore (University of Illinois at Urbana-Champaign) and A.Yu. Rusanov, V.A. Oboznov, V.V. Bolginov, A.N. Rossolenko, and V.V. Ryazanov (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.H1.1