Cryogen-free one hundred microKelvin refrigerator

TL;DR

This paper reports a cryogen-free dilution refrigerator capable of reaching temperatures below 100 microKelvin, maintaining such low temperatures for over 10 hours, with independently controlled high magnetic fields.

Contribution

It introduces a novel cryogen-free system achieving sub-100 microKelvin temperatures with long stability and independent high magnetic field control.

Findings

Achieved below 100 microKelvin temperature in a cryogen-free setup.

Maintained sub-100 microKelvin temperature for over 10 hours.

Controlled magnetic fields up to 9 T and 12 T independently.

Abstract

Temperature below 100 microKelvin is achieved in a customized cryogen-free dilution refrigerator with a copper-nuclear demagnetization stage. The lowest temperature of conduction electrons of the demagnetization stage is below 100 microKelvin as measured by a pulsed platinum NMR thermometer and the temperature can remain below 100 microKelvin for over 10 hours. An up to 9 T demagnetization magnetic field and an up to 12 T research magnetic field can be controlled independently, provided by a coaxial room-temperature-bore cryogen-free magnet.