Flux transistor made from a single-layer niobium thin-film superconducting quantum interference device

Abstract

A micrometre-size Josephson vortex flow transistor is demonstrated experimentally. The drain-source of this device is the output of a single-layer Nb superconducting quantum interference device (SQUID) with a nanometre-size hole, forming a nanoSQUID. The device input is a Nb strip, which is closely coupled to the nanoSQUID. The change of the input current induces a change in the magnetic flux coupling to the nanoSQUID, and hence modulates the current-voltage characteristics of the nanoSQUID. The current gain and transresistance of the device were investigated by evaluating the mutual coupling and the dynamic resistance of the nanoSQUID. A current gain of 0.3 and a transresistance >1 were achieved.

Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

“…In this framework, the nanoSQUID have been proposed as a flux flow transistor [278] and trapped-vortex memory device [278]. As regard as the transistor, Lam [279] demonstrated that a Josephson nanodevice, including a nanoSQUID (similar to that shown in Fig. 21) and a single Nb strip, can acts as a gate and employed as three-terminal device (Fig.…”

Hysteretic behaviour of nanoSQUIDs—prospective application as trapped-vortex memory

“…In order to minimize the required write current, the Nb strip has to be close to the nanoSQUID. Our previous work indicates that a write current of less than 200 μA can couple a magnetic flux of ∼0.5 o into the nanoSQUID, a very promising result [22].…”

“…For a practical memory cell, a control line would be used to manipulate the flux state of each cell. This can be achieved by using a Nb strip patterned closely to the nanoSQUID [18,22]. In order to minimize the required write current, the Nb strip has to be close to the nanoSQUID.…”

Why NanoSQUIDs are important: an introduction to the focus issue

“…There has been some development of various three-terminal devices based on nanoSQUIDs in both all Nb [31] and hybrid Nb-carbon nanotubes [9]. The hybrid carbon nanotube threeterminal device uses gate-tunable carbon nanotubes (CNTs) for the Josephson junctions.…”