Temperature Below 30 mK Achieved by Adiabatic Demagnetization Refrigeration

作者：Qiaofei Xu, Xin‐Yang Liu, Ruo‐Tong Wu, Ming-Yang Fu, Man-Ting Chen, Junsen Xiang, Yin‐Shan Meng, Tao Liu, Peijie Sun, La‐Sheng Long, Lan-Sun Zheng · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.5c10483 · 被引用次数：6 · 研究领域：Magnetic and transport properties of perovskites and related materials、Optical properties and cooling technologies in crystalline materials、Advanced Condensed Matter Physics

Adiabatic demagnetization refrigeration (ADR) is the only technique capable of reaching ultralow temperatures without helium-3 and plays a crucial role at the forefront of both fundamental and applied science. However, progress in ADR is constrained by the limited magnetic entropy change (−Δ S m ) of existing refrigerants at ultralow temperatures. This limitation primarily stems from the inherent contradiction of simultaneously attaining a large −Δ S m and a low magnetic ordering temperature ( T 0 ) in magnetic refrigerant design. Here, we show that a magnetic refrigerant exhibiting both a large −Δ S m and a low T 0 can be simultaneously achieved by incorporating weak magnetic exchange and dipolar interactions into the dense frustrated magnet KYb 3 F 10 ( 1 ). Notably, the average −Δ S m of 1 in the 0.05–1.0 K range surpasses those of commercial refrigerants (NH 4 )Fe(SO 4 ) 2 ·12H 2 O and CrK(SO 4 ) 2 ·12H 2 O by 146 and 219%, respectively, while its T 0 is lower than 50 mK. Practical ADR testing confirms that a minimum temperature of 27.2 mK can be reached under a magnetic field of 6 T using 1 as the refrigerant. Thus, this work not only presents a high-performance ultralow-temperature refrigerant but also addresses the long-standing challenge of simultaneously achieving a large −Δ S m and a low T 0 in the design of magnetic refrigerants.