We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF2(H2O)(2)](2) pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 squarelattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the quasi-two-dimensional lattice into weakly coupled chains. We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction studies with quantitative modeling using spin-polarized density functional theory.

Giant Pressure Dependence and Dimensionality Switching in a Metal-Organic Quantum Antiferromagnet

Wehinger B.
;
2018

Abstract

We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF2(H2O)(2)](2) pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 squarelattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the quasi-two-dimensional lattice into weakly coupled chains. We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction studies with quantitative modeling using spin-polarized density functional theory.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10278/3720463
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