9 research outputs found
Ferromagnetic Josephson Junctions for High Performance Computation
Josephson junctions drive the operation of superconducting qubits and they are the key for the coupling and the interfacing of superconducting qubit components with other quantum platforms. They are the only means to introduce non linearity in a superconducting circuit and offer direct solutions to tune the properties of a superconducting qubit, thus enlarging the possible qubit layouts. Junctions performances and tunability can take advantage of using a large variety of barriers and their special functionalities. We mention pertinent results on the advances in understanding the properties of ferromagnetic junctions, which make possible the use of these devices either as memory elements and as core circuit elements
Resonant phonon-magnon interactions in free-standing metal-ferromagnet multilayer structures
We analyze resonant magneto-elastic interactions between standing
perpendicular spin wave modes (exchange magnons) and longitudinal acoustic
phonon modes in free-standing hybrid metal-ferromagnet bilayer and trilayer
structures. Whereas the ferromagnetic layer acts as a magnetic cavity, all
metal layers control the frequencies and eigenmodes of acoustic vibrations. The
here proposed design allows for achieving and tuning the spectral and spatial
modes overlap between phonons and magnons that results in their strong resonant
interaction. Realistic simulations for gold-nickel multilayers show that
sweeping the external magnetic field should allow for observing resonantly
enhanced interactions between individual magnon and phonon modes in a broad
range of frequencies spanning from tens of GHz up to several hundreds of GHz,
which can be finely tuned through the multilayer design. Our results would
enable the systematic study and the deep understanding of resonantly enhanced
magneto-elastic coupling between individual phonon and magnon modes up to
frequencies of great contemporary fundamental and applied interest.Comment: 9 pages, 6 figure
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 uV 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 ~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.Comment: 10 pages, 4 figure
Properties of ferromagnetic Josephson junctions for memory applications
In this work we give a characterization of the RF effect of memory switching
on Nb-Al/AlOx-(Nb)-PdFe-Nb Josephson junctions as a function
of magnetic field pulse amplitude and duration, alongside with an
electrodynamical characterization of such junctions, in comparison with
standard Nb-Al/AlOx-Nb tunnel junctions. The use of microwaves to tune the
switching parameters of magnetic Josephson junctions is a step in the
development of novel addressing schemes aimed at improving the performances of
superconducting memories.Comment: IEEE Trans. Appl. Supercond. Special Issue ISEC201
SUPERCONDUCTOR ANALOG TO DIGITAL CONVERTER FOR SIGINT APPLICATIONS
ABSTRACT Superconductor analog-to-digital converters (ADC) offe