Project

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Magnetic Excitations in Low-Dimensional Arrays of Quantum Spins

Applicant Krämer Karl
Number 132877
Funding scheme Project funding (Div. I-III)
Research institution Departement für Chemie und Biochemie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Condensed Matter Physics
Start/End 01.01.2011 - 31.12.2013
Approved amount 418'568.00
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All Disciplines (2)

Discipline
Condensed Matter Physics
Inorganic Chemistry

Keywords (13)

spin Luttinger-liquids; Bose-Einstein condensation; thermodynamic measurements; bond randomness; Ising spin systems; materials science; Quantum magnetism; Spin Luttinger-liquids; Bose-Einstein condensation; Quantum phase transitions; Magnetic excitations; Neutron scattering; Materials science

Lay Summary (English)

Lead
We propose a major new initiative to discover and synthesize novel copper- and cobalt-based materials. These compounds will serve as model systems in which the fundamental phases, exotic order, and elementary excitations of quantum magnets with low-dimensional lattices, random exchange interactions, and reduced spin symmetry will be studied by neutron spectroscopy and bulk experimental techniques.
Lay summary
Project A: Novel quantum phases and phase transitions in spin ladder
systems with random exchange: The particular focus will be to
utilize the inherent chemical flexibility and structural tunability of the
metal-organic spin ladder material (C5H12N)2CuBr4 to study the
effects of bond randomness and later also non-magnetic and magnetic
impurities on the spin Luttinger-liquid and Bose-Einstein Condensate
physics discovered in this compound. Specifically, we want to search
for a Bose glass phase, characterize anomalous thermal transport
properties near the quantum critical points, and measure the
elementary excitations and detailed spectral functions of the
randomized quantum spin ladder at low temperatures and in high
magnetic fields.
Project B: Dynamics and quantum phase transitions in Ising spin systems:
Extending our synthesis and inelastic neutron scattering activities to
Co-based Ising spin systems, we shall 1) perform high-resolution
studies employing new spectrometers to known model systems, and
2) develop new model materials with suitable energy scale and low
dimensionality, as well as unexplored coupling geometries.
Project C: New synthetic routes to future reference materials: Progress in
quantum magnetism relies on the discovery of new close-ideal model
systems. Keeping in mind model systems of greatest current interest,
we shall strengthen our exploratory chemistry work by combining
‘top-down’ crystal engineering based on selected ligands (oxalate and
squarate) with detailed magnetic characterization of new promising
compounds – own and from literature.
Direct link to Lay Summary Last update: 04.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
The coordination chemistry of tartronic acid with copper: magnetic studies of a quasi-equilateral tricopper triangle
Pascu G., Deville C., Clifford S. E., Guenée L., Besnard C., Krämer K. W., Liu S. X., Decurtins S., Tuna F., McInnes E. J. L., Winpenny R. E. P., Williams A. F. (2014), The coordination chemistry of tartronic acid with copper: magnetic studies of a quasi-equilateral tricopper triangle, in Dalton Transactions, 43, 656-662.
Functionalized Adamantane Tectons Used in the Design of Mixed- Ligand Copper(II) 1,2,4-Triazolyl/Carboxylate Metal−Organic Frameworks
Senchyk G., Lysenko A., Krautscheid H., Rusanov E., Chernega A., Krämer K.W., Liu S.X., Decurtins S., Domasevitch K. (2013), Functionalized Adamantane Tectons Used in the Design of Mixed- Ligand Copper(II) 1,2,4-Triazolyl/Carboxylate Metal−Organic Frameworks, in Inorg. Chem., 52, 863-872.
Functionalized Adamantane Tectons Used in the Design of Mixed-Ligand Copper(II) 1,2,4-Triazolyl/Carboxylate Metal−Organic Frameworks
Senchyk G. A., Lysenko A. B., Krautscheid H., Rusanov E. B., Chernega A. N., Krämer K. W., Liu S. X., Decurtins S., Domasevitch K. (2013), Functionalized Adamantane Tectons Used in the Design of Mixed-Ligand Copper(II) 1,2,4-Triazolyl/Carboxylate Metal−Organic Frameworks, in Inorg. Chem. , 52, 863-872.
Phase diagram with an enhanced spin-glass region of the mixed Ising–XY magnet LiHoxEr1-xF4
Piatek J. O., Dalla Piazza B., Nikseresht N., Tsyrulin N., Živković I., Krämer K. W., Laver M., Prokes K., Mataš S., Christensen N. B., Rønnow H. M. (2013), Phase diagram with an enhanced spin-glass region of the mixed Ising–XY magnet LiHoxEr1-xF4, in Phys. Rev. B , 88, 014408-11.
Spin ladders and quantum simulators for Tomonaga-Luttinger liquids
Ward S., Bouillot P., Ryll H., Kiefer K., Krämer K. W., Rüegg Ch., Kollath C., Giamarchi T. (2013), Spin ladders and quantum simulators for Tomonaga-Luttinger liquids, in J. Phys.: Cond. Matt. , 25, 014004-7.
(C5H12N)Cu2Br3: A Piperidinium Copper(I) Bromide with [Cu2Br3]− Ladders
Komm T., Biner D., Neels A., Krämer K.W. (2012), (C5H12N)Cu2Br3: A Piperidinium Copper(I) Bromide with [Cu2Br3]− Ladders, in Crystals, 2(4), 1434-1440.
Dipolar antiferromagnetism and quantum criticality in LiErF4
Kraemer C., Nikseresht N., Piatek J.O., Tsyrulin N., Dalla Piazza B., Kiefer K., Klemke B., Rosenbaum T.F., Aeppli G., Ganarelli C., Prokes K., Podlesniyak A., Strässle T., Keller L., Zaharko O., Krämer K.W., Ronnow H.M. (2012), Dipolar antiferromagnetism and quantum criticality in LiErF4, in Science, 336, 1416-1419.
Site-selective quantum correlations revealed by magnetic anisotropy in the tetramer system SeCuO3
Zivkovic I., Djokic D. M., Herak M., Pajic D., Prsa K., Pattison P., Dominko D., Mickovic Z., Cincic D., Forro L., Berger H., Ronnow H. M. (2012), Site-selective quantum correlations revealed by magnetic anisotropy in the tetramer system SeCuO3, in Phys. Rev. B, 86, 054405-9.
Spin ladders and quantum simulators for Tomonaga–Luttinger liquids
Ward S., Bouillot P., Ryll H., Kiefer K., Krämer K.W., Rüegg C., Kollath C., Giamarchi T. (2012), Spin ladders and quantum simulators for Tomonaga–Luttinger liquids, in J. Phys.: Condens. Matter, 25, 014004-7.
Complete bond-operator theory of the two-chain spin ladder
Normand B., Rüegg Ch. (2011), Complete bond-operator theory of the two-chain spin ladder, in PHYSICAL REVIEW B, 83, 054415-12.
Direct Observation of Local Mn-Mn Distances in the Paramagnetic Compound CsMnxMg1-xBr3
Furrer A., Strässle T., Embs J. P., Juranyi F., Pomjakushin V., Schneider M., Krämer K. W. (2011), Direct Observation of Local Mn-Mn Distances in the Paramagnetic Compound CsMnxMg1-xBr3, in PHYSICAL REVIEW LETTERS, 107, 115502-5.
Pair correlations, short-range order, and dispersive excitations in the quasi-kagome quantum magnet volborthite
Nilsen G. J., Coomer F. C., de Vries M. A., Stewart J. R., Deen P. P., Harrison A., Rønnow H. M. (2011), Pair correlations, short-range order, and dispersive excitations in the quasi-kagome quantum magnet volborthite, in PHYSICAL REVIEW B, 84, 172401-4.
Single-ion versus two-ion anisotropy in magnetic compounds: A neutron scattering study
Furrer A., Juranyi F., Krämer K. W., Schneider M., Strässle T. (2011), Single-ion versus two-ion anisotropy in magnetic compounds: A neutron scattering study, in PHYSICAL REVIEW B, 83, 024404-8.
Spangolite: an s=1/2 maple leaf lattice antiferromagnet?
Fennell T., Piatek J. O., Stephenson R. A., Nilsen G. J., Rønnow H. M. (2011), Spangolite: an s=1/2 maple leaf lattice antiferromagnet?, in J. Phys.: Cond. Matt., 23, 164201-6.
The magnetic structure of multiferroic BaMnF4
Poole A., Roessli B., Zaharko O., Krämer K. W. (2011), The magnetic structure of multiferroic BaMnF4, in J. Phys.: Condens. Matter, 23, 266004-5.
Two-dimensional coordination compounds based on Fe(II) and Co(III) hexacyanometallates with Cu(II)(dien) groups: Structures and magnetic properties
Keene T. D., Komm T., Hauser J., Krämer K. W. (2011), Two-dimensional coordination compounds based on Fe(II) and Co(III) hexacyanometallates with Cu(II)(dien) groups: Structures and magnetic properties, in INORGANICA CHIMICA ACTA, 373(1), 100-106.

Collaboration

Group / person Country
Types of collaboration
Laboratory of Magnetic Measurements, Helmholtz Zentrum Berlin Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Institut Laue Langevin, Grenoble France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
London Centre for Nanotechnology, University College London Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
105175 Magnetic excitations in low-dimensional compounds of transition metal ions 01.01.2005 Project funding (Div. I-III)
150713 ZEBRA - a new neutron single-crystal diffractometer optimized for small samples and extreme conditions 01.11.2014 R'EQUIP
150257 Dimensional and Anisotropy Control of Model Quantum Magnets 01.01.2014 Project funding (Div. I-III)
117817 Magnetic excitations in novel metal-organic quantum materials and molecular magnets 01.01.2008 Project funding (Div. I-III)
172659 New materials for honeycomb-lattice and single-ion magnets 01.08.2017 Project funding (Div. I-III)
139082 Sensitive magnetic susceptibility measurements of materials with novel magnetic correlations and ground states 01.07.2012 R'EQUIP
121397 Sub-Kelvin high sensitivity magnetometer for magnetic materials exploration 01.07.2008 R'EQUIP
144972 High efficiency neutron spectrometer optimized for investigations under extreme conditions 01.01.2014 R'EQUIP
65120 Magnetic Neutron Scattering of Low Dimensional Transition Metal Ion Compounds 01.01.2002 Project funding (Div. I-III)
146870 Quantum Magnetism - Spinons, Skyrmions and Dipoles 01.04.2013 Project funding (Div. I-III)

Abstract

We propose a major new initiative to discover and synthesize novel copper- and cobalt-based materials. These compounds will serve as model systems in which the fundamental phases, exotic order, and elementary excitations of quantum magnets with low-dimensional lattices, random exchange interactions, and reduced spin symmetry will be studied by neutron spectroscopy and bulk experimental techniques. Project A focuses on novel quantum phases and phase transitions in spin ladder systems with random exchange. Materials for project A are derivatives of (C5H12N)2CuBr4.Project B investigates the dynamics and quantum phase transitions in Ising spin systems. Here complex cobalt halides are in the focus of interest.Project C aims on the synthesis of new model systems based on oxalate and squarate ligands.
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