Magnetic cooling for microkelvin nanoelectronics on a cryofree platform

Area of Science:

• Low-temperature physics
• Nanotechnology
• Quantum computing

Background:

• Cooling nanoelectronic devices to sub-millikelvin temperatures is crucial for advancing quantum technologies.
• Existing refrigeration methods face limitations in achieving and maintaining ultra-low temperatures for sensitive devices.

Purpose of the Study:

• To present a novel parallel network of 16 nuclear refrigerators designed for cooling nanoelectronic devices.
• To characterize the performance of this system, including its base temperature, heat load capacity, and cooling efficiency.

Main Methods:

• Utilizing a cryofree dilution refrigerator integrated with a parallel network of 16 nuclear demagnetization refrigerators.
• Employing a noise thermometer based on electron thermal motion in a silver wire, detected by a superconducting gradiometer and SQUID amplifier.
• Characterizing system performance using multiple thermometers and a thermal model.

Main Results:

• Achieved a lowest temperature of 150 μK in one nuclear stage.
• Identified magnetic field-independent heat leaks of a few nW/mol.
• Demonstrated cold times of several days below 1 mK.
• Observed high refrigerator efficiencies exceeding 80%.

Conclusions:

• The developed parallel nuclear refrigerator network effectively cools nanoelectronic devices to sub-millikelvin temperatures.
• The system exhibits robust performance with low heat leaks and long cold times.
• A validated thermal model accurately describes the system's behavior, confirming high operational efficiency.