Fe-Gd Ferromagnetic Cyclic Coordination Cluster [FeIII4GdIII4(teaH)8(N3)8(H2O)] with Magnetic Anisotropy─Theory and Experiment

Dirk Schray; Dennis Westerbeck; Jonas Braun; Yanhua Lan; Silvia Gómez-Coca; Wolfgang Wernsdorfer; Eliseo Ruiz; Christopher E Anson; Jürgen Schnack; Annie K Powell

doi:10.1021/acs.inorgchem.3c00042

Fe-Gd Ferromagnetic Cyclic Coordination Cluster [Fe^III₄Gd^III₄(teaH)₈(N₃)₈(H₂O)] with Magnetic Anisotropy─Theory and Experiment

Inorg Chem. 2023 May 1;62(17):6642-6648. doi: 10.1021/acs.inorgchem.3c00042. Epub 2023 Apr 17.

Authors

Dirk Schray¹, Dennis Westerbeck², Jonas Braun^{1

3}, Yanhua Lan¹, Silvia Gómez-Coca⁴, Wolfgang Wernsdorfer^{3

5

6}, Eliseo Ruiz⁴, Christopher E Anson¹, Jürgen Schnack², Annie K Powell^{1

3

6}

Affiliations

¹ Institute of Inorganic Chemistry (AOC), Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany.
² Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany.
³ Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
⁴ Departament de Química Inorgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
⁵ Physikalisches Institut (PHI), Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131 Karlsruhe, Germany.
⁶ Institute for Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

PMID: 37068219
DOI: 10.1021/acs.inorgchem.3c00042

Abstract

The synthesis, structural, and magnetic characterization of [Fe^III₄Ln^III₄(teaH)₈(N₃)₈(H₂O)] (Ln = Gd and Y) and the previously reported isostructural Dy analogue are discussed. The commonly held belief that both Fe^III and Gd^III can be regarded as isotropic ions is shown to be an oversimplification. This conclusion is derived from the magnetic data for the Y^III analogue in terms of the zero-field splitting seen for Fe^III and from the fact that the magnetic data for the new Gd^III analogue can only be fit employing an additional anisotropy term for the Gd^III ions. Furthermore, the Fe₄Gd₄ ring shows slow relaxation of magnetization. Our analysis of the experimental magnetic data employs both density functional theory as well as the finite-temperature Lanczos method which finally enables us to provide an almost perfect fit of magnetocaloric properties.