A Magnetic Persistent Current Switch at milliKelvin Temperatures

TL;DR

This paper presents a magnetic persistent current switch designed for operation at milliKelvin temperatures, demonstrating its ability to charge large coils with minimal residual resistance in a dilution refrigerator.

Contribution

It introduces a novel magnetic switch suitable for ultra-low temperature environments and provides experimental validation of its performance and minimal residual resistance.

Findings

Successfully charged a 60 mH coil with 0.5 A at 11 mK

Residual resistance measured at 4 K is ≤ 3.3 pΩ

Heats the refrigerator to only 60.5 mK during operation

Abstract

We report the development of a magnetically driven Persistent Current Switch operated in a dilution refrigerator. We show that it can be safely used to charge a 60 mH coil with 0.5 A at 11 mK, which heats up the dilution refrigerator to 60.5 mK. Measurements at 4 K on a 440 $\mu$H coil reveal a residual resistance of $R \leqslant 3.3$ p$\Omega$.