Magnetic cooling technology based on magnetocaloric effect (MCE) has attracted great interest in obtaining extremely low temperatures, for example, for space exploration. Here, we grew a new gadolinium-rich orthoborate K3 Li3 Gd7 (BO3 )9 (1) as a promising cryogenic magnetic coolant. It exhibits a complicated three dimensional framework constructed from BO3 groups and gadolinium-oxygen chains. The Gd-O chain consists of two types of clusters of Gd3 O20 and Gd3 O19 interconnection by Gd(4)O8 polyhydron. Due to its high gadolinium concentration, a large -ΔSm of 56.6 J kg-1 K-1 for 1 was obtained at 2 K and ΔH=7 T, much larger than that of the commercial benchmark Gd3 Ga5 O12 (GGG) crystal (38.4 J kg-1 K-1 ), suggesting it to be an excellent MCE material.
Keywords: cryogenics; gadolinium borate; gadolinium clusters; magnetocaloric effects; polar structures.
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