We report the characteristic magnetic properties of several members of the
rare earth garnet family, Gd3βGa5βO12β (GGG), Dy3βGa5βO12β
(DGG), Tb3βGa5βO12β (TGG), and Nd3βGa5βO12β (NGG), and compare
their relative potential utility for magnetocaloric cooling, including their
minimal adiabatic demagnetisation refrigeration (ADR) temperatures and relative
cooling parameters. A main objective of this work was to find potential
improvements over the magnetocaloric properties of GGG for use in low
temperature ADR cryostats. Using Tb+3 and Dy+3 in the RE-site offers
in principle higher saturation magnetisation and Nd+3 gives a lower de
Gennes factor and therefore potentially low transition temperature. Our results
show that Dy3βGa5βO12β yields an optimal relative cooling parameter
(RCP) at low applied fields and a low transition temperature, which would
allow for the design of more efficient ADR cryostats.Comment: 10 pages, 10 figures, submitted to Physical Review Applie