Flux compensation for SQUID-detected Magnetic Resonance Force Microscopy

TL;DR

This paper introduces an on-chip feedback coil method to cancel RF crosstalk in SQUID-detected MRFM at milliKelvin temperatures, enabling advanced magnetic resonance experiments.

Contribution

The paper presents a novel flux compensation technique using an on-chip feedback coil that effectively cancels RF crosstalk without additional nearby components.

Findings

Almost complete flux crosstalk negation up to several $\

0\

Abstract

One of the major challenges in performing SQUID-detected Magnetic Resonance Force Microscopy (MRFM) at milliKelvin temperatures is the crosstalk between the radiofrequency (RF) pulses used for the spin manipulation and the SQUID-based detection mechanism. Here we present an approach based on balancing the flux crosstalk using an on-chip feedback coil coupled to the SQUID. This approach does not require any additional components near the location of the sample, and can therefore be applied to any SQUID-based detection scheme to cancel predictable RF interference. We demonstrate the effectiveness of our approach by showing that we can almost completely negate flux crosstalk with an amplitude of up to several $\Phi_0$. This technical achievement allows for complicated magnetic resonance protocols to be performed at temperatures below 50 mK.