Chirality and Magnetocaloricity in GdFeTeO(6) as Compared to GdGaTeO(6)

GdFeTeO(6) and GdGaTeO(6) have been prepared and their structures refined by the Rietveld method. Both are superstructures of the rosiaite type (space group [Formula: see text]). Their thermodynamic properties have been investigated by means of magnetization M and specific heat C(p) measurements, evidencing the formation of the long-range antiferromagnetic order at T(N) = 2.4 K in the former compound and paramagnetic behavior down to 2 K in the latter compound. Large magnetocaloric effect allows considering GdFeTeO(6) for the magnetic refrigeration at liquid hydrogen stage. Density functional theory calculations produce estimations of leading Gd–Gd, Gd–Fe and Fe–Fe interactions suggesting unique chiral 120° magnetic structure of Fe(3+) (S = 5/2) moments and Gd(3+) (J = 7/2) moments rotating in opposite directions (clockwise/anticlockwise) within weakly coupled layers of the rosiaite type crystal structure.