Dual on-chip SQUID measurement protocol for flux detection in large magnetic fields

TL;DR

This paper introduces a dual on-chip SQUID measurement protocol that enables sensitive flux detection in large magnetic fields, crucial for quantum spin detection and quantum computing applications.

Contribution

A novel differential flux measurement setup using two DC-SQUIDs with pulsed readout to reduce background noise and minimize heating in high magnetic fields.

Findings

Successful proof of concept experiment demonstrated enhanced flux sensitivity.

Effective background flux cancellation achieved with differential measurement.

Protocol maintains low on-chip heating suitable for quantum coherence preservation.

Abstract

Sensitive magnetometers that can operate in high magnetic fields are essential for detecting magnetic resonance signals originating from small ensembles of quantum spins. Such devices have potential applications in quantum technologies, in particular quantum computing. We present a novel experimental setup implementing a differential flux measurement using two DC-SQUID magnetometers. The differential measurement allows for cancellation of background flux signals while enhancing sample signal. The developed protocol uses pulsed readout which minimizes on-chip heating since sub-Kelvin temperatures are needed to preserve quantum spin coherence. Results of a proof of concept experiment are shown as well.