Giant pressure dependence and dimensionality switching in a metal-organic quantum antiferromagnet

We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [(CuF\(_2\)(H\(_2\)O)\(_2\))\(_2\)pyrazine]. At zero pressure, this material realizes a quasi-two-dimensional (Q2D) spin-1/2 square-lattice Heisenberg antiferromagnet. By high-pressure, high-field...

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Bibliographic Details
Published in:arXiv.org 2018-02
Main Authors: Wehinger, Björn, Fiolka, Christoph, Lanza, Arianna, Scatena, Rebecca, Kubus, Mariusz, Grockowiak, Audrey, Coniglio, William A, Graf, David, Skoulatos, Markos, Chen, Jyong-Hao, Gukelberger, Jan, Casati, Nicola, Zaharko, Oksana, Macchi, Piero, Krämer, Karl W, Tozer, Stan, Mudry, Christopher, Normand, Bruce, Rüegg, Christian
Format: Article
Language:English
Subjects:
Antiferromagnetism
Density functional theory
Magnetic permeability
Neutron diffraction
Neutrons
Phase transitions
Pressure dependence
Switches
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Summary:We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [(CuF\(_2\)(H\(_2\)O)\(_2\))\(_2\)pyrazine]. At zero pressure, this material realizes a quasi-two-dimensional (Q2D) spin-1/2 square-lattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 upon compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the Q2D lattice into weakly coupled chains (Q1D). We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction results with quantitative modeling using spin-polarized density functional theory.
ISSN:2331-8422
DOI:10.48550/arxiv.1606.08344