Development of the integrated sorption cooler for an adiabatic demagnetization refrigerator (ADR)

Ultralow-field magnetocaloric materials for compact magnetic refrigeration

“…In contrast, current magnetic refrigerators can only be operated under large magnetic fields, and superconducting magnets are mandatory. For example, Kwon et al designed a refrigerator consisting of a sorption cooler and an adiabatic demagnetization refrigerator, in which the magnetic working medium was GGG under a magnetic field of 40 kOe 17 . It has been recognized that the volume or weight of the superconducting magnets accounts for approximately one-third of the whole system 39 .…”

“…In 1973, Fisher et al systematically studied the thermomagnetic properties of gallium gadolinium garnet (GGG) single crystals along the [001], [110], and [111] directions, and the maximum ΔS m reached 38 J kg −1 K −1 under a magnetic field change of 70 kOe [13][14][15] . Since then, GGG has become the primary choice for commercial adiabatic demagnetization refrigerators around the liquid-helium temperature as well as a benchmark for magnetocaloric materials exploration 16,17 . Although an increasing number of low-temperature magnetocaloric materials with large ΔS m values have been reported [18][19][20][21][22] to satisfy the growing demands for space exploration and quantum computation, strong magnetic fields are usually needed, which are currently only provided by heavy and large superconducting magnets.…”