Magnetic and Magnetocaloric Properties of the A2LnSbO6 Lanthanide Oxides on the Frustrated fcc Lattice

Frustrated lanthanide oxides are promising candidatesfor cryogen-freemagnetic refrigeration due to their suppressed ordering temperaturesand high magnetic moments. While much attention has been paid to thegarnet and pyrochlore lattices, the magnetocaloric effect in frustratedface-centered cubic (fcc) lattices remains relativelyunexplored. We previously showed that the frustrated fcc double perovskite Ba2GdSbO6 is a top-performingmagnetocaloric material (per mol Gd) because of its small nearest-neighborinteraction between spins. Here we investigate different tuning parametersto maximize the magnetocaloric effect in the family of fcc lanthanide oxides, A(2)LnSbO(6) (A = {Ba2+, Sr2+} and Ln = {Nd3+, Tb3+, Gd3+, Ho3+, Dy3+, Er3+}), includingchemical pressure via the A site cation and the magnetic ground statevia the lanthanide ion. Bulk magnetic measurements indicate a possibletrend between magnetic short-range fluctuations and the field-temperaturephase space of the magnetocaloric effect, determined by whether anion is a Kramers or a non-Kramers ion. We report for the first timeon the synthesis and magnetic characterization of the Ca(2)LnSbO(6) series with tunable site disorder that can be usedto control the deviations from Curie-Weiss behavior. Takentogether, these results suggest fcc lanthanide oxidesas tunable systems for magnetocaloric design. We investigate different tuning parameters to maximize themagnetocaloric effect in fcc lanthanide oxides, A(2)LnSbO(6) (A = {Ba2+, Sr2+}and Ln = {Nd3+, Tb3+, Gd3+, Ho3+, Dy3+, Er3+}), including chemicalpressure via the A site cation and the magnetic ground state via thelanthanide ion. Bulk magnetic measurements indicate a possible trendbetween magnetic short-range fluctuations and the field-temperaturephase space of the magnetocaloric effect, determined by whether anion is a Kramers or a non-Kramers ion. The Ca(2)LnSbO(6) series has tunable site disorder that can be used to controlthe deviations from Curie-Weiss behavior.

Automated summary

By adjusting different parameters of fcc lanthanide oxides, such as chemical pressure via the A site cation and the magnetic ground state via the lanthanide ion, the magnetocaloric effect can be maximized for magnetic refrigeration design. This study also introduces the Ca(2)LnSbO(6) series with tunable site disorder that can control the deviations from Curie-Weiss behavior.