Frustrated lanthanide oxides are promising candidates
for cryogen-free
magnetic refrigeration due to their suppressed ordering temperatures
and high magnetic moments. While much attention has been paid to the
garnet and pyrochlore lattices, the magnetocaloric effect in frustrated
face-centered cubic (fcc) lattices remains relatively
unexplored. We previously showed that the frustratedfccdouble perovskite Ba2GdSbO6is a top-performing
magnetocaloric material (per mol Gd) because of its small nearest-neighbor
interaction between spins. Here we investigate different tuning parameters
to maximize the magnetocaloric effect in the family offcclanthanide oxides, A2LnSbO6(A = {Ba2+, Sr2+} and Ln = {Nd3+, Tb3+, Gd3+, Ho3+, Dy3+, Er3+}), including
chemical pressure via the A site cation and the magnetic ground state
via the lanthanide ion. Bulk magnetic measurements indicate a possible
trend between magnetic short-range fluctuations and the field-temperature
phase space of the magnetocaloric effect, determined by whether an
ion is a Kramers or a non-Kramers ion. We report for the first time
on the synthesis and magnetic characterization of the Ca2LnSbO6series with tunable site disorder that can be used
to control the deviations from Curie–Weiss behavior. Taken
together, these results suggestfcclanthanide oxides
as tunable systems for magnetocaloric design.