Data associated with "Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites"
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Dutton, S., Koskelo, E., Liu, C., Kelly, N., & Mukherjee, P. (2022). Data associated with "Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites" [Dataset]. https://doi.org/10.17863/CAM.82520
Data associated with the publication 'Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites.' Frustrated lanthanide oxides with dense magnetic lattices are of fundamental interest for their potential in cryogenic refrigeration due to a large ground state entropy and suppressed ordering temperatures, but can often be limited by short-range correlations. Here, we present examples of frustrated fcc oxides, Ba2GdSbO6 and Sr2GdSbO6 and the new site-disordered analog Ca2GdSbO6 ([CaGd]A[CaSb]BO6), in which the magnetocaloric effect is influenced by minimal superexchange (J1 ∼ 10 mK). We report on the crystal structures using powder x-ray diffraction and the bulk magnetic properties through low-field susceptibility and isothermal magnetization measurements. The Gd compounds exhibit a magnetic entropy change of up to -15.8 J/K/molGd in a field of 7 T at 2 K, a 20% excess compared to the value of -13.0 J/K/molGd for a standard in magnetic refrigeration, Gd3Ga5O12. Heat capacity measurements indicate a lack of magnetic ordering down to 0.4 K for Ba2GdSbO6 and Sr2GdSbO6, suggesting cooling down through the liquid 4-He regime. A mean-field model is used to elucidate the role of primarily free spin behavior in the magnetocaloric performance of these compounds in comparison to other top-performing Gd-based oxides. The chemical flexibility of the double perovskites raises the possibility of further enhancement of the magnetocaloric effect in the Gd3+ fcc lattices. Please see readme file for details on contents of folders
All data is in open file format. CIF files can be opened in standard crystal structure viewers.
Magnetocalorics, Perovskites, X-ray diffraction
This work was supported through the EP/T028580/1 EPSRC grant and the Winton Programme for the Physics of Sustainability. The work of E.C.K. was supported by a Churchill Scholarship from the Winston Churchill Foundation of the United States. N.D.K. gratefully acknowledges the EPSRC for the provision of a PhD Studentship (EP/R513180/1). Magnetic measurements at Cambridge were made on the EPSRC Advanced Characterization Suite EP/M0005/24/1. We acknowledge Diamond Light Source for time on I11 under BAG proposal CY28349 and Dr. Sarah Day for collecting the data.
Engineering and Physical Sciences Research Council (EP/P007767/1)
This record's DOI: https://doi.org/10.17863/CAM.82520
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/