Experimental and Theoretical Characterization of the Magnetic Properties of CuF2(H2O)2(pyz) (pyz = pyrazine): A Two-Dimensional Quantum Magnet Arising from Supersuperexchange Interactions through Hydrogen Bonded Paths

Manson, Jamie L.; Conner, Marianne M.; Schlueter, John A.; McConnell, Amber C.; Southerland, Heather I.; Malfant, Isabelle; Lancaster, Tom; Blundell, Stephen J.; Brooks, Michael; Pratt, F. L.; Singleton, John; McDonald, R. D.; Lee, Chang‐Hoon; Whangbo, Myung‐Hwan

doi:10.1021/cm8016566

Cited by 59 publications

(52 citation statements)

References 42 publications

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“…The value of T N determined from the powerlaw fit is slightly smaller than the value reported by muon spin relaxation measurements of a non-deuterated sample 5,8 but is in reasonable agreement with the value of T N = 2.53 K determined from magnetic susceptibility measurements of fully deuterated samples.…”

Section: Resultssupporting

confidence: 84%

“…Note that the z-axis is the spin wave quantization direction, in this case the real-space [0.7 0 1] direction. This same spin anisotropy may be related to the observed low-field spinflop like transition observed for CuF 2 (H 2 O) 2 (pyz) 5 The spin wave dispersion has been examined along the antiferromagnetic zone boundary. In Fig.…”

mentioning

confidence: 53%

“…First principles electronic structure calculations confirm this configuration. 5 These calculations give an intra-plane AFM exchange interaction of about 13 to 19 K and an inter-plane AFM exchange interaction of only 1% of the intra-plane exchange interaction. An important feature of CuF 2 (H 2 O) 2 (pyz) is that under an applied pressure of 0.9 GPa, a switch of the Jahn-Teller axis from the N-Cu-N to the O-Cu-O (c direction) bond occurs.…”

Section: 6mentioning

confidence: 88%

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Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
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We have performed elastic and inelastic neutron scattering experiments on single crystal samples of the coordination polymer compound CuF2(H2O)2(pyz) (pyz=pyrazine) to study the magnetic structure and excitations. The elastic neutron diffraction measurements indicate a collinear antiferromagnetic structure with moments oriented along the [0.7 0 1] real-space direction and an ordered moment of 0.60 ± 0.03 µB/Cu. This value is significantly smaller than the single ion magnetic moment, reflecting the presence of strong quantum fluctuations. The spin wave dispersion from magnetic zone center to the zone boundary points (0.5 1.5 0) and (0.5 0 1.5) can be described by a two dimensional Heisenberg model with a nearest neighbor magnetic exchange constant J 2d = 0.934 ± 0.0025 meV. The inter-layer interaction Jperp in this compound is less than 1.5% of J 2d . The spin excitation energy at the (0.5 0.5 0.5) zone boundary point is reduced when compared to the (0.5 1 0.5) zone boundary point by ∼ 10.3 ± 1.4 %. This zone boundary dispersion is consistent with quantum Monte Carlo and series expansion calculations for the S=1/2 Heisenberg square lattice antiferromagnet which include corrections for quantum fluctuations to linear spin wave theory.

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Section: Resultssupporting

confidence: 84%

mentioning

confidence: 53%

Section: 6mentioning

confidence: 88%

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Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
16
3
11
0
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“…The magnetic lattice in a low-dimensional system is not always obvious from an inspection of the crystal structure [17,29]. Verification of the equivalence of the magnetic and structural planes and chains in our materials comes from the angle-dependence of the g-factor as determined by electron-spin resonance.…”

mentioning

confidence: 96%

“…In such situations, the unpaired spin in a d 9 configuration is expected to occupy the d x 2 −y 2 orbital [30], and the g-factor parallel to the distorted zaxis takes a larger value than those in the xy-plane (see discussion in Ref. 29). Accordingly, the data in Fig.…”

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confidence: 99%

Dimensionality Selection in a Molecule-Based Magnet

et al. 2012

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Gaining control of the building blocks of magnetic materials and thereby achieving particular characteristics will make possible the design and growth of bespoke magnetic devices. While progress in the synthesis of molecular materials, and especially coordination polymers, represents a significant step towards this goal, the ability to tune the magnetic interactions within a particular framework remains in its infancy. Here we demonstrate a chemical method which achieves dimensionality selection via preferential inhibition of the magnetic exchange in an S = 1/2 antiferromagnet along one crystal direction, switching the system from being quasi-two-to quasi-one-dimensional while effectively maintaining the nearest-neighbour coupling strength.Coordination polymers are self-organising materials consisting of arrays of metal ions linked via molecular ligands, with non-coordinated counterions supplying charge neutrality. The choice of initial components permits a high level of control over the final product, enabling many different polymeric architectures to be obtained [1]. These materials provide a route to successful crystal engineering, and a number of functionalities are being actively studied, including gas storage [2-4], optoelectronic [5,6], ferroelectric [7,8] and magnetic properties [9-14].Although it is now possible to generate an assortment of disparate magnetic lattices using this method [15,16], true control of magnetic exchange interactions implies an ability to adjust selected parameters while keeping others constant. To this end, a series of coordination polymers based on Cu(II) ions bridged by pyrazine (C 4 H 4 N 2 ) molecules have proven to be highly versatile. In these systems it has been shown that it is possible to alter significantly the primary exchange energies via adjustment of the ligands [17] and the counterions [18, S9], or fine-tune the exchange by a few percent via isotopic substitution [20], all the while maintaining the same basic metal-pyrazine network. In this paper we demonstrate the power of this strategy by chemically engineering a reduction in the dimensionality of a magnetic system. After first designing a material based on coordinated planes of Cu(II), we adapt the recipe such that the ligand bridges are broken along a specific crystal direction, resulting in a chain-like compound. Because the ligand mediating the magnetic interactions in both cases is unchanged, the nearest-neighbour exchange energies of the two materials are found to be equal to each other to within 5%. The difference in numbers of nearest-neighbours, however, means that the strength of the combined exchange interactions acting on each magnetic ion in the quasitwo-dimensional material is twice that of its quasi-onedimensional cousin.Figs. 1(a) and (b) show the crystal structure of orthorhombic [Cu(pyz) 2 (pyO) 2 ](PF 6 ) 2 (where pyz = pyrazine and pyO = pyridine-N -oxide, C 5 H 5 NO) determined using single-crystal x-ray diffraction [21]. S = 1/2 Cu ions are linked by pyz molecules into nearly square planar ...

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Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

et al. 2010

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Druckabhängige Isomerisierung: Die Manipulation der Struktur‐Eigenschafts‐Beziehungen des Kupfer(II)‐Koordinationsnetzwerks CuF2(H2O)2(pyz) (pyz=Pyrazin) mit Druck ergab, dass die lange Jahn‐Teller‐Achse zwischen den N‐Cu‐N‐ (<0.9 GPa), O‐Cu‐O‐ (0.9–3.1 GPa) und F‐Cu‐F‐Bindungen wechselt (>3.1 GPa) (siehe Bild). Diese Orbitalumordnung führt zu einer drastischen Änderung der magnetischen Eigenschaften, wobei die magnetische Struktur oberhalb 0.9 GPa von einer zwei‐ in eine eindimensionale Geometrie übergeht.

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Experimental and Theoretical Characterization of the Magnetic Properties of CuF₂(H₂O)₂(pyz) (pyz = pyrazine): A Two-Dimensional Quantum Magnet Arising from Supersuperexchange Interactions through Hydrogen Bonded Paths

Abstract: 2.64 K '(T) plot for a polycrystalline sample of CuF 2 (H 2 O) 2 (pyz). H dc = 0 Oe, H ac = 1 Oe, = 125 Hz.

Cited by 59 publications

References 42 publications

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
16
3
11
0
View full text Add to dashboard Cite

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
16
3
11
0
View full text Add to dashboard Cite

Dimensionality Selection in a Molecule-Based Magnet

Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

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Experimental and Theoretical Characterization of the Magnetic Properties of CuF2(H2O)2(pyz) (pyz = pyrazine): A Two-Dimensional Quantum Magnet Arising from Supersuperexchange Interactions through Hydrogen Bonded Paths

Abstract: 2.64 K '(T) plot for a polycrystalline sample of CuF 2 (H 2 O) 2 (pyz). H dc = 0 Oe, H ac = 1 Oe, = 125 Hz.

Cited by 59 publications

References 42 publications

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2Wang1, Lumsden2, Fishman3 et al. 2012Phys. Rev. B163110View full textAdd to dashboardCite

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2Wang1, Lumsden2, Fishman3 et al. 2012Phys. Rev. B163110View full textAdd to dashboardCite

Dimensionality Selection in a Molecule-Based Magnet

Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

Contact Info

Product

Resources

About

Experimental and Theoretical Characterization of the Magnetic Properties of CuF₂(H₂O)₂(pyz) (pyz = pyrazine): A Two-Dimensional Quantum Magnet Arising from Supersuperexchange Interactions through Hydrogen Bonded Paths

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
16
3
11
0
View full text Add to dashboard Cite

Magnetic properties of theS=12quasisquare lattice antiferromagnet CuF2(H2
Wang
¹
,
Lumsden
²
,
Fishman
³

et al. 2012
Phys. Rev. B
16
3
11
0
View full text Add to dashboard Cite