Investigation of Proximity-induced Superconductivity in Platinum Nanowires
Open Access
- Author:
- Slotcavage, Daniel John
- Area of Honors:
- Physics
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Thomas E Mallouk, Thesis Supervisor
Moses Hung Wai Chan, Thesis Honors Advisor
Christine Masters, Thesis Honors Advisor
Judith A Todd Copley, Faculty Reader - Keywords:
- Proximity effect
superconductivity
nanowires
platinum nanowires
mini-gap state
magnetoresistance - Abstract:
- Nanowires, due to their extremely small diameters, offer a unique platform for researchers to investigate the quasi-1-dimensional electron transport regime. At such small scales, quantum effects begin to dominate and we observe unique physical phenomena. The proximity effect, in which two superconducting electrodes sandwich a non-superconducting metal and force it to exhibit weak signs of superconductivity, is one such phenomenon. This study utilizes nanowires to explore some of the physical effects that result from the proximity effect in 1D systems. In single-crystal gold nanowires, researchers have recently shown the existence of a so-called 'mini-gap state', a state of intermediate resistance in an applied magnetic field caused by two distinct gaps in the nanowire. The same study showed periodic oscillations in differential magnetoresistance caused by the motion of individual vortices within the nanowire. This study employs platinum nanowires to attempt to reproduce the results found in the gold nanowires in a different but similar noble metal. Synthesis of single-crystal platinum nanowires via chemical electrodeposition has not been shown in the past. In this study, we add gelatin and vary electrochemical potential, temperature, and pH in a platinum plating solution in order to increase grain size and eventually grow single-crystal platinum nanowires. Current results, however, show only short, polycrystalline platinum nanowires. We test polycrystalline platinum nanowires with diameters of 50nm or 150nm with various electrode spacings in order to find the mini-gap state and probe for periodic oscillations in differential magnetoresistance. Results for the smaller diameter nanowires have been consistent with the gold nanowires previously tested in the literature, but the existence of a mini-gap state in polycrystalline platinum nanowires has not yet been proven. The wider nanowires show extremely odd behaviors that may be due to errors in sample fabrication, and require further investigation.