Ferromagnetic Josephson switching device with high characteristic voltage

We develop a fast magnetic Josephson junction (MJJ)-a superconducting ferromagnetic device for a scalable high-density cryogenic memory compatible in speed and fabrication with energy-efficient single flux quantum (SFQ) circuits. We present experimental results for superconductor-insulator-ferromagnet-superconductor (SIFS) MJJs with high characteristic voltage IcRn of > 700 mu V proving their applicability for superconducting circuits. By applying magnetic field pulses, the device can be switched between MJJ logic states. The MJJ IcRn product is only similar to 30% lower than that of conventional junction co-produced in the same process, allowing for integration of MJJ-based and SIS-based ultra-fast digital SFQ circuits operating at tens of gigahertz. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4723576]