Data associated with "Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites"
Citation
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
Description
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.
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Format
All data is in open file format. CIF files can be opened in standard crystal structure viewers.
Keywords
Magnetocalorics, Perovskites, X-ray diffraction
Relationships
Sponsorship
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.
Funder references
Engineering and Physical Sciences Research Council (EP/P007767/1)
EPSRC (EP/T028580/1)
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.82520
Rights
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/
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