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Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials
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Ultralow-Temperature Magnetic Refrigeration Inorganic Materials: From Designed Synthesis to Adiabatic Demagnetization
Qiao-Fei Xu1, Ruo-Tong Wu1, La-Sheng Long1
1Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Accounts of Chemical Research
|August 29, 2025
Summary
Researchers developed new magnetic refrigerants for adiabatic demagnetization refrigeration (ADR) that achieve high magnetic entropy changes (-ΔSm) and low ordering temperatures (T0). These novel materials significantly advance helium-free cooling below 1 Kelvin for quantum computing and astronomy.
Area of Science:
- Materials Science
- Low-Temperature Physics
- Quantum Technologies
Background:
- Adiabatic demagnetization refrigeration (ADR) is the only helium-free technology for sub-Kelvin cooling.
- Growing demand in quantum computing and astronomy necessitates advanced ADR systems.
- Existing magnetic refrigerants face a trade-off between magnetic entropy change (-ΔSm) and ordering temperature (T0).
Purpose of the Study:
- To rationally design next-generation magnetic refrigerants for ADR.
- To overcome the challenge of achieving high -ΔSm and low T0 simultaneously.
- To enhance ADR performance for millikelvin temperature applications.
Main Methods:
- Tuning magnetic parameters: ordering temperature (T0), exchange, and dipolar interactions.
- Incorporating fluoride bridges into antiferromagnetic frameworks.
- Utilizing mean-field approximation and quantum Monte Carlo (QMC) simulations.
- Synthesizing and testing novel materials like Gd(OH)F2, LiGd0.1Yb0.9F4, and KYb3F10.
Main Results:
- Fluoride incorporation shifted antiferromagnetism to weak ferromagnetism, lowering T0 and increasing -ΔSm.
- Gd(OH)F2 achieved record -ΔSm values by balancing weak magnetic interactions and high magnetic density.
- LiGd0.1Yb0.9F4 cooled to 160 mK with double the cooling capacity of commercial refrigerants.
- KYb3F10 reached 27.2 mK, demonstrating promise as a next-generation ADR refrigerant.
Conclusions:
- Rational design strategies successfully enhance -ΔSm and suppress T0 in magnetic refrigerants.
- Balancing competing magnetic interactions and chemical disorder is key to high performance.
- The developed refrigerants provide a robust pathway for advancing ADR technology in fundamental and applied low-temperature systems.
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