KAIST Develops Compact Cryocooler Using Magnetic Field Variation

2025-01-29

A research team led by Professor Sang-Kwon Jeong of the Department of Mechanical Engineering at the Korea Advanced Institute of Science and Technology (KAIST) has developed a compact cryocooler (Cryogenic Cooling System) capable of achieving ultra-low temperatures close to absolute zero using variations in magnetic fields. Cryocoolers are used to maintain extremely low temperatures to stabilize devices such as space-based sensors and quantum computers. Conventionally, dilution refrigerators using a mixture of helium-3 and helium-4 isotopes are employed to achieve cryogenic temperatures. However, helium-3 is expensive and has a low density, requiring a circulation system, which results in a large system size.

The research team has developed a cryocooler that can achieve ultra-low temperatures in a compact size without using helium-3. The adsorption cooler used for this purpose regulates the temperature of the adsorbent by utilizing the adsorption phenomenon where gas adheres to the surface of adsorbents such as activated carbon and generates a cooling effect by evaporating liquid helium. Additionally, the cryocooler system was miniaturized by using a superconducting magnet that enables magnetic compression and expansion of magnetic materials.

The magnetic material is pre-cooled to approximately 1.5 K using a commercial refrigerator and an adsorption cooler, and then further cooled to a final temperature of 0.3 K (-272.85 degrees Celsius) through changes in the magnetic field of the superconducting magnet.

Source: https://www.daejonilbo.com/news/articleView.html?idxno=2174161