Novel application of adiabatic demagnetization refrigeration

Herein, novel techniques and applications for adiabatic demagnetization refrigeration (ADR) are explored for their use in dry cryogenic systems such as Bluefors dilution refrigerators. In addition to using special copper flakes as an “in-cell” coolant [1, 2], quantum spin-1 Heisenberg materials, such as Heisenberg antiferromagnetic chains (HAFC), are explored as ADR candidates to provide improved cooling capabilities [3]. Unlike copper, these materials allow for finite magnetic fields measurements at base temperature below 10 mK. Finite temperature algorithms such as the minimally entangled typical thermal states (METTS) simulated the thermal properties of candidate materials. The details of experimental results of the novel application of copper flake nuclear spin coolants and the progress on identifying candidates for quantum coolants will be reported.

[1] R.C.M. Dow, et al. J Low Temp Phys 47 (1982) 477

[2] D.I. Bradley, et al. J Low Temp Phys 57 (1984) 359.

[3] T. Liu, et al. Phys Rev Research 3 (2021) 033094.