Closed-cycle superconducting magnet system with optical access for THz spectroscopy applications.
Abstract
Funding is provided for the purchase of a closed-cycle superconducting magnet system with optical access for THz spectroscopy applications.This project proposes the acquisition of a closed-cycle superconducting magnet with optical access, to be housed in the PI’s laboratory at Georgetown University. It will support her ongoing ONR-related collaborative research with the Naval Research Laboratory and the University of Stuttgart. Specifically, it will be used for terahertz spectroscopy studies of single-molecule magnets (SMMs) grafted on highly-sensitive graphene quantum dot bolometers. The grafting will be with monolayer coverage, or with just a few molecules on each dot, to study how the coupling to the molecules affects quantum transport through a dot. The proposed system will provide magnetic fields up to 7 T, a variable temperature insert for sample temperature from 1.5 K to 300 K and four optical windows. It will be a substantial upgrade of the current superconducting magnet operating in liquid helium. The objectives pursued are: • A faster and more thorough characterization of quantum dot bolometers in the presence of magnetic field and terahertz radiation, both before SMM grafting, to understand how the formation of Landau levels will affect the terahertz detection properties, and after SMM grafting, to study how the coupling between the molecules and the dots affects quantum transport. • Terahertz absorption measurements of samples after SMM grafting and after highfrequency electron paramagnetic resonance characterization at the University of Stuttgart, to test robustness of properties after shipment with a different experimental set-up. The methods to be employed will use facilities already available in the PI’s laboratory for the current superconducting magnet. The advantage of the new system is that it will not need the purchase and transfer of expensive liquid helium to cool down, thereby allowing more frequent measurements. It will also provide easier optical access and alignment, with rotation capabilities to change the orientation of cold samples with respect to the magnetic field.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 10, 2017
- Source ID
- N000141712436
Entities
People
- Paola Barbara
Organizations
- Georgetown University
- Office of Naval Research
- United States Navy