Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

Halder, Gregory J.; Chapman, Karena W.; Schlueter, John A.; Manson, Jamie L.

doi:10.1002/anie.201003380

Cited by 56 publications

(97 citation statements)

References 13 publications

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“…These interactions have proven fruitful to realize materials sensitive to external stimuli such as high pressure 12–14 or high electric fields 15 . Over the past decade, we have focused on the design, synthesis and physical characterization of open-shell transition metal coordination complexes, molecules and polymers, based on Cu(II) ( S = 1/2), Ni(II) ( S = 1) and Co(II) ( S = 3/2) ions that contain the poly-HF adducts HF 2 − , H 2 F 3 − and H 3 F 4 − which have been shown, on occasion, to be effective mediators of magnetic exchange interactions 16–22 .…”

Section: Introductionmentioning

confidence: 99%

Implications of bond disorder in a S=1 kagome lattice

Manson

Brambleby

Goddard

et al. 2018

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Strong hydrogen bonds such as F···H···F offer new strategies to fabricate molecular architectures exhibiting novel structures and properties. Along these lines and, to potentially realize hydrogen-bond mediated superexchange interactions in a frustrated material, we synthesized [H2F]2[Ni3F6(Fpy)12][SbF6]2 (Fpy = 3-fluoropyridine). It was found that positionally-disordered H2F+ ions link neutral NiF2(Fpy)4 moieties into a kagome lattice with perfect 3-fold rotational symmetry. Detailed magnetic investigations combined with density-functional theory (DFT) revealed weak antiferromagnetic interactions (J ~ 0.4 K) and a large positive-D of 8.3 K with ms = 0 lying below ms = ±1. The observed weak magnetic coupling is attributed to bond-disorder of the H2F+ ions which leads to disrupted Ni-F···H-F-H···F-Ni exchange pathways. Despite this result, we argue that networks such as this may be a way forward in designing tunable materials with varying degrees of frustration.

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Section: Introductionmentioning

confidence: 99%

Implications of bond disorder in a S=1 kagome lattice

Manson

Brambleby

Goddard

et al. 2018

Sci Rep

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“…An added advantage of molecular systems is the ability to make controlled adjustments to the crystal structure, thereby tuning interaction strengths and better testing the predictions of the SLHAFM and associated models. To this end, we and others have previously shown that it is possible to gain a degree of control over the primary exchange energy in low-dimensional molecular antiferromagnets via constitutional changes that include deuteration 18 , anion substitution 11,19 , exchange of halide ligands 20,21 , and the application of high pressures 22,23 .…”

Section: Introductionmentioning

confidence: 99%

Control of the third dimension in copper-based square-lattice antiferromagnets

et al. 2016

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Using a mixed-ligand synthetic scheme, we create a family of quasi-two-dimensional antiferromagnets, namely, [Cu(HF2)(pyz)2]ClO4 [pyz = pyrazine], [CuL2(pyz)2](ClO4)2 [L = pyO = pyridine-N-oxide and 4-phpyO = 4-phenylpyridine-N-oxide. These materials are shown to possess equivalent two-dimensional [Cu(pyz)2] 2+ nearly square layers, but exhibit interlayer spacings that vary from 6.5713Å to 16.777Å, as dictated by the axial ligands. We present the structural and magnetic properties of this family as determined via x-ray diffraction, electron-spin resonance, pulsed-and quasistatic-field magnetometry and muon-spin rotation, and compare them to those of the prototypical two-dimensional magnetic polymer Cu(pyz)2(ClO4)2. We find that, within the limits of the experimental error, the two-dimensional, intralayer exchange coupling in our family of materials remains largely unaffected by the axial ligand substitution, while the observed magnetic ordering temperature (1.91 K for the material with the HF2 axial ligand, 1.70 K for the pyO and 1.63 K for the 4-phpyO) decreases slowly with increasing layer separation. Despite the structural motifs common to this family and Cu(pyz)2(ClO4)2, the latter has significantly stronger two-dimensional exchange interactions and hence a higher ordering temperature. We discuss these results, as well as the mechanisms that might drive the long-range order in these materials, in terms of departures from the ideal S = 1/2 two-dimensional square-lattice Heisenberg antiferromagnet. In particular, we find that both spin exchange anisotropy in the intralayer interaction and interlayer couplings (exchange, dipolar, or both) are needed to account for the observed ordering temperatures, with the intralayer anisotropy becoming more important as the layers are pulled further apart.

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“…1 Current interest in such materials is driven by the rich variety of magnetic ground and excited states that can be observed, especially at high magnetic fields, low temperatures or high pressures. In order to better understand the underlying magnetism of these systems it is imperative that we understand the underlying relationship between the lattice and spin dimensionality, and if at all possible, the microscopic magnetic structure, as it can reveal phenomena not observed by macroscopic measurement techniques.…”

Section: Introductionmentioning

confidence: 99%

“…The structural and magnetic diversity of metal-halides can be expanded even further by incorporation of organic Lewis bases such as pyrazine (pyz), 1b–1e,5 pyrazine- N , N′ -dioxide (pyzdo) 6 , tetrahydrofuran (THF), 7 pyridine (py), 8 2,2 ′ -bipyridine (2,2′-bipy) 9 and 4,4 ′ -bipyridine (4,4 ′ -bipy) 10 just to list a few. Interesting physical properties presented by these materials include, but are not limited to, antiferromagnetism (AFM), ferrimagnetism (FIM), ferromagnetism (FM), and metamagnetism (MM), the particular state depending on the metal ion, its oxidation number and presence of spin-exchange anisotropy.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Structure and Exchange Interactions in Quasi-One-Dimensional MnCl₂(urea)₂

et al. 2015

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MnCl2(urea)2 is a new linear chain coordination polymer that exhibits slightly counter-rotated MnCl4 rhomboids along the chain-axis. The material crystallizes in the non-centrosymmetric orthorhombic space group Iba2, with each Mn(II) ion equatorially surrounded by four Cl− that lead to bi-bridged ribbons. Urea ligands coordinate via O-atoms in the axial positions. Hydrogen bonds of the Cl⋯H-N and O⋯H-N type link the chains into a quasi-3D network. Magnetic susceptibility data reveal a broad maximum at 9 K that is consistent with short-range magnetic order. Pulsed-field magnetization measurements conducted at 0.6 K show that a fully polarized magnetic state is achieved at Bsat = 19.6 T with a field-induced phase transition occurring at 2.8 T. Neutron diffraction studies made on a powdered sample of MnCl2(urea)2 reveal that long-range magnetic order occurs below TN = 3.2(1) K. Additional Bragg peaks due to antiferromagnetic (AFM) ordering can be indexed according to the Ib’a2’ magnetic space group and propagation vector τ = [0, 0, 0]. Rietveld profile analysis of these data reveal a Néel-type collinear ordering of Mn(II) ions with an ordered magnetic moment of 4.06(6) μB (5 μB is expected for isotropic S = 5/2) oriented along the b-axis, i.e., perpendicular to the chain-axis that runs along the c-direction. Owing to potential for spatial exchange anisotropy and the pitfalls in modeling bulk magnetic data, we analyzed inelastic neutron scattering data to retrieve the exchange constants; Jc = 2.22 K (intrachain), Ja = −0.10 K (interchain) and D = −0.14 K with J > 0 assigned to AFM coupling. This J configuration is most unusual and contrasts the more commonly observed case of AFM-coupled FM-chains.

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Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

Cited by 56 publications

References 13 publications

Implications of bond disorder in a S=1 kagome lattice

Implications of bond disorder in a S=1 kagome lattice

Control of the third dimension in copper-based square-lattice antiferromagnets

Magnetic Structure and Exchange Interactions in Quasi-One-Dimensional MnCl₂(urea)₂

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Pressure‐Induced Sequential Orbital Reorientation in a Magnetic Framework Material

Cited by 56 publications

References 13 publications

Implications of bond disorder in a S=1 kagome lattice

Implications of bond disorder in a S=1 kagome lattice

Control of the third dimension in copper-based square-lattice antiferromagnets

Magnetic Structure and Exchange Interactions in Quasi-One-Dimensional MnCl2(urea)2

Contact Info

Product

Resources

About

Magnetic Structure and Exchange Interactions in Quasi-One-Dimensional MnCl₂(urea)₂