Highly-sensitive superconducting quantum interference proximity transistor

Abstract

We report the design and implementation of a high-performance superconducting quantum interference proximity transistor (SQUIPT) based on aluminum-copper (Al-Cu) technology. With the adoption of a thin and short copper nanowire we demostrate full phase-driven modulation of the proximity-induced minigap in the normal metal density of states. Under optimal bias we record unprecedently high flux-to-voltage (up to 3 mV/${\Phi }_0$) and flux-to-current (exceeding 100 nA/${\Phi }_0$) transfer function values at sub-Kelvin temperatures, where ${\Phi }_0$ is the flux quantum. The best magnetic flux resolution (as low as 500 n${\Phi }_0/\sqrt{Hz}$ at 240 mK, being limited by the room temperature pre-amplification stage) is reached under fixed current bias. These figures of merit combined with ultra-low power dissipation and micrometer-size dimensions make this mesoscopic interferometer attractive for low-temperature applications such as the investigation of the magnetization of small spin populations.

7 pages, 5 color figures

References in corpus (3)

• Phase controlled superconducting proximity effect probed by tunneling spectroscopy
• Density of states and supercurrent in diffusive SNS junctions: role of nonideal interfaces and spin-flip scattering
• Josephson current in nanofabricated V/Cu/V mesoscopic junctions

Cited by in corpus (3)

• Proximity nanovalve with large phase-tunable thermal conductance
• Spectral characteristics of a fully-superconducting SQUIPT
• Noise of a superconducting magnetic flux sensor based on a proximity Josephson junction