Simulation and experimental realization of vector-potential sensors by quasilocal superconducting objects
Abstract
A recent theoretical breakthrough obtained under the support of the ONR Grant N00014-16-1-2269 predicted a way of detecting the influence of external curl-less vector potentials in superconducting quasilocal objects. Namely, the generation and further evolution of Abrikosov single-quantum vortices is sensitive to the presence of the external curl-less vector potential. This is definitely a quantum mechanically based effect, but it is expected to have classically detectable corollaries: it may provide a way of detecting electromagnetic fields even when the related classical quantities, as the magnetic or electric fields, are zero (absent). This breakthrough was obtained from the time-dependent Ginzburg-Landau (TDGL) set of self-consistent equations using finite element modeling based on the COMSOL Multiphysics package. In order to move toward the experimental realization of vector-potential sensors, in this effort the modeling will be extended to account for the next level of detailed factors which may be present in the practical tests of the effect. For example, fabricating samples with feature sizes on magnetic penetration depth scales (<40 nm for Nb) is not routine on the same samples as make SQUIDs and other integrated test circuit components in a 8 metal layer, whole wafer process. In parallel, the design of the experiments will be analyzed with potential experimental partners and collaborators, so as to insure that confounding effects do not obscure our results. The initial experimental concept is to use the ultralow field option of the Quantum Design PPMS cryostat, which was purchased under the auspices of the ONR DURIP program last year. Some additional options would be required to allow this cryostat to fulfill this demanding task. We plan to apply to this year s DURIP competition to implement the required upgrades, in particular, the ferromagnetic resonance spectroscopy probe with Helmholtz coils and RF-fixtures for the required high-frequency electronics application in the nonmagnetic environment in the cryostat. If that additional grant proposal fails, we will use a homemade system within the reach of the support under the current proposal which can be considered as “plan B”. Regarding samples preparation, the Advanced Physics Lab of Chapman U. has all the major facilities, starting with thin film deposition, characterization, patterning, wirebonding and testing. However, we will be open for collaborative effort during the last two years, in case the ONR will arrange partnership grants with participants such as University of Illinois or HYPRES. Such kinds of arrangement will enhance access to higher quality Niobium films, utilize previously accumulated expertise of specialists in different related fields, and enhance the expectation of positive outcome. While the experimental realization of the vector-potential sensor is the major goal of the proposal, some additional tasks will be solved via modeling during the last two years of the project, after the design and overall experimental realization will be launched during year one. These include generating an insight into physics of 2D and 3D Josephson junctions and SQUIDs via finite-element COMSOL modeling, visualization of RSFQ-pulse propagation in superconducting electronics circuits and the distinctions between Abrikosov and Josephson vortices on the same basis, and in particular, the influence of geometrically-generated spurious signals on RSFQ-based circuit operation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 03, 2017
- Source ID
- N000141712972
Entities
People
- Armen Gulian
Organizations
- Chapman University
- Office of Naval Research
- United States Navy