Synthese und Kristallstruktur von Ba6Lu4Zn10O22 mit [OBa6]‐Oktaedern

Rabbow, Ch.; Müller‐Buschbaum, Hk.

doi:10.1002/zaac.19966220115

Cited by 10 publications

(10 citation statements)

References 22 publications

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“…The structure was studied via neutron powder diffraction utilizing the POW-GEN [47] diffractometer at the Spallation Neutron Source at Oak Ridge National Laboratory [45]. These measurements confirm the previously reported cubic structure [33,48,49] (space group F43m, no. 216) with lattice parameter a=13.47117(3) at 10 K and a=13.48997(3) at 300 K.…”

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confidence: 71%

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Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.

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The low energy spin excitation spectrum of the breathing pyrochlore Ba 3 Yb 2 Zn 5 O 11 has been investigated with inelastic neutron scattering. Several nearly resolution limited modes with no observable dispersion are observed at 250 mK while, at elevated temperatures, transitions between excited levels become visible. To gain deeper insight, a theoretical model of isolated Yb 3+ tetrahedra parametrized by four anisotropic exchange constants is constructed. The model reproduces the inelastic neutron scattering data, specific heat, and magnetic susceptibility with high fidelity. The fitted exchange parameters reveal a Heisenberg antiferromagnet with a very large Dzyaloshinskii-Moriya interaction. Using this model, we predict the appearance of an unusual octupolar paramagnet at low temperatures and speculate on the development of inter-tetrahedron correlations.Frustrated or competing interactions have been repeatedly found to be at the root of many unusual phenomena in condensed matter physics [1][2][3][4][5]. By destabilizing conventional long-range order down to low temperature, frustration in magnetic systems can lead to many exotic phases; from unconventional multipolar [6,7] and valence bond solid orders [1,4] to disordered phases such as classical and quantum spin liquids [1,4]. Significant attention has been devoted to understanding geometric frustration where it is the connectivity of the lattice that hinders the formation of order. Recently, however, magnets frustrated not by geometry but by competing interactions have become prominent for the novel behaviors that they host. Such competing interactions might be additional isotropic exchange acting beyond nearest neighbors [8-10], biquadratic or other multipolar interactions [11]. One possibility attracting ever increasing interest is that competing strongly anisotropic interactions may stabilize a wide range of unusual phenomena.An exciting research direction in the latter context concerns itself with so-called "quantum spin ice" [12]. This quantum spin liquid can be stabilized by perturbing classical spin ice with additional anisotropic transverse exchange interactions that induce quantum fluctuations. Particularly interesting is the potential realization of such physics in the rare-earth pyrochlores R 2 M 2 O 7 [13][14][15], where R is a trivalent 4 f rare-earth ion, and M is a non-magnetic tetravalent transition metal ion, such as M=Ti, Sn or Zr. These materials can be described in terms of pseudo spin-1/2 degrees of freedom interacting via anisotropic exchanges [12,15], where the effective spin-1/2 maps the states of the crystal-electric field ground doublet of the rare-earth ion. These materials display a wealth of interesting phenomena, from the possibility of quantum [16][17][18] ion is part of a large and small tetrahedron in the breathing pyrochlore lattice.liquids [22,23]. In many of these compounds, the physics is very delicate, showing strong sample to sample variations [24] or sensitivity to very small amounts of disorder [25,26]. Consequen...

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confidence: 71%

“…bond has symmetry C 2v (2mm) and each small Yb 4 tetrahedron has full tetrahedral symmetry T d (43m) [33,49]. Assuming an effective spin-1/2 doublet [52], there are therefore four allowed anisotropic exchange interactions [15], taking the form…”

mentioning

confidence: 99%

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.

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“…The crystal structure of this family was solved by the single crystal X-ray diffraction (XRD) technique [21,22]. They crystallize in the unique structure with the cubic space group F43m, in which the A 4 O 16 cluster and Zn 10 O 20 super-tetrahedron align alternatively and Ba ions fill the interstices, as depicted in [22] was used as a starting model and, subsequently, the atomic positions and isotropic atomic displacement parameters of Ba, Yb, and Zn sites were refined. Three 2θ ranges exhibiting very weak peaks for impurities were excluded from the refinement [23].…”

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confidence: 99%

Experimental realization of a quantum breathing pyrochlore antiferromagnet

2014

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The synthesis and characterization of a new Yb-based material Ba 3 Yb 2 Zn 5 O 11 are reported.This material is identified as the first model system of a pseudospin-1/2 quantum antiferromagnet on "breathing" pyrochlore lattice characterized by an alternating array of small and large Yb tetrahedra. Despite dominant antiferromagnetic interactions J ∼ 7 K, a large amount of magnetic entropy (25%) remains at 0.38 K, indicating that each small Yb tetrahedron forms a unique doubly degenerate singlet state. These results are well described by the Heisenberg pseudospin-1/2 single tetrahedron model.

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“…At this point, neutron scattering experiments are crucially needed to check whether the system might be in the ice manifold and whether quantum spin ice QSL physics appears below 0.38K. It will also be interesting to look for QSL physics in other breathing pyrochlore systems with other rare earth elements 44 . Indeed, in general, based on our theoretical results, breathing pyrochlores appear as a promising playground for the discovery of quantum spin ice physics and novel quantum phase transitions, and certainly warrant further investigation.…”

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confidence: 99%

Quantum spin ice on the breathing pyrochlore lattice

et al. 2016

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The Coulombic quantum spin liquid in quantum spin ice is an exotic quantum phase of matter that emerges on the pyrochlore lattice and is currently actively searched for. Motivated by recent experiments on the Yb-based breathing pyrochlore material Ba 3 Yb 2 Zn 5 O 11 , we theoretically study the phase diagram and magnetic properties of the relevant spin model. The latter takes the form of a quantum spin ice Hamiltonian on a breathing pyrochlore lattice, and we analyze the stability of the quantum spin liquid phase in the absence of the inversion symmetry which the lattice breaks explicitly at lattice sites. Using a gauge mean-field approach, we show that the quantum spin liquid occupies a finite region in parameter space. Moreover, there exists a direct quantum phase transition between the quantum spin liquid phase and featureless paramagnets, even though none of theses phases break any symmetry. At nonzero temperature, we show that breathing pyrochlores provide a much broader finite-temperature spin liquid regime than their regular counterparts. We discuss the implications of the results for current experiments and make predictions for future experiments on breathing pyrochlores.

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Synthese und Kristallstruktur von Ba₆Lu₄Zn₁₀O₂₂ mit [OBa₆]‐Oktaedern

Cited by 10 publications

References 22 publications

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.

Experimental realization of a quantum breathing pyrochlore antiferromagnet

Quantum spin ice on the breathing pyrochlore lattice

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Synthese und Kristallstruktur von Ba6Lu4Zn10O22 mit [OBa6]‐Oktaedern

Cited by 10 publications

References 22 publications

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5Rau1, Wu2, May3 et al. 2016Phys. Rev. Lett.

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5Rau1, Wu2, May3 et al. 2016Phys. Rev. Lett.

Experimental realization of a quantum breathing pyrochlore antiferromagnet

Quantum spin ice on the breathing pyrochlore lattice

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Product

Resources

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Synthese und Kristallstruktur von Ba₆Lu₄Zn₁₀O₂₂ mit [OBa₆]‐Oktaedern

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing PyrochloreBa3Yb2Zn5
Rau
¹
,
Wu
²
,
May
³

et al. 2016
Phys. Rev. Lett.