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Quantum Frustration in Model Magnets

English title Quantum Frustration in Model Magnets
Applicant Rüegg Christian
Number 140862
Funding scheme Project funding
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Condensed Matter Physics
Start/End 01.07.2012 - 30.11.2015
Approved amount 375'183.00
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Keywords (7)

Spin ice; Frustrated magnetism; Magnetic structures; Magnetic x-ray scattering; Materials science; Neutron scattering; Magnetic excitations

Lay Summary (English)

Lead
Competition of interactions or so-called frustration between magnetic moments leads to fascinating new states of matter in magnetic materials. The goal of this major new initiative is to experimentally explore these new states in two families of frustrated magnets - spinels and pyrochlores - using advanced neutron and X-ray scattering techniques. Our results will shed light on some of the greatest mysteries in frustrated magnetism, help to understand these novel states, and possibly enable us to utilize them in future devices.
Lay summary

Frustrated magnets are fascinating materials of high current interest. In these magnets competing interactions between magnetic ions lead to novel states of matter. Our studies focus on well-developed model systems such as so-called spin ice materials, as well as on the first studies of new compounds using advanced microscopic probes such as neutron and x-ray scattering at the Paul Scherrer Institut and at other facilities in Europe. We will investigate systems with different dimensionalities and geometries of the atomic lattice and contrasting classical and quantum spins.

A triangular lattice of quantum spins is a candidate for a quantum spin-liquid ground state, which is one of the proposed exotic states. We will explore prototypical frustrated magnets by neutron and x-ray scattering to determine their crystal structures at low temperature, magnetic order, and excitations. Neutron and x-ray scattering are exceptionally sensitive and well-suited probes for the study of these properties.

The existence of many possible ground states is a key feature of frustrated magnets. These ground states are the background in which exotic excitations can propagate.  In the case of the spin ice materials, these excitations are very new, so-called magnetic monopoles. However, the mechanism of their propagation is unknown. The main focus of the project is to measure these and examine their interactions.  

Direct link to Lay Summary Last update: 22.06.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Spiral spin-liquid and the emergence of a vortex-like state in MnSc2S4
Gao Shang, Zaharko Oksana, Tsurkan Vladimir, Su Yixi, White Jonathan S., Tucker Gregory S., Roessli Bertrand, Bourdarot Frederic, Sibille Romain, Chernyshov Dmitry, Fennell Tom, Loidl Alois, Rüegg Christian (2017), Spiral spin-liquid and the emergence of a vortex-like state in MnSc2S4, in Nature Physics, 13(2), 157-161.
Phonon-mediated spin-flipping mechanism in the spin ices Dy2Ti2O7 and Ho2Ti2O7
Ruminy M., Chi S., Calder S., Fennell T. (2017), Phonon-mediated spin-flipping mechanism in the spin ices Dy2Ti2O7 and Ho2Ti2O7, in Physical Review B, 95(6), 060414-060414.
Neutron Larmor diffraction investigation of the rare-earth pyrochlores R2Ti2O7 ( R=Tb , Dy, Ho)
Ruminy M., Groitl F., Keller T., Fennell T. (2016), Neutron Larmor diffraction investigation of the rare-earth pyrochlores R2Ti2O7 ( R=Tb , Dy, Ho), in Physical Review B, 94(17), 174406-174406.
Crystal-field parameters of the rare-earth pyrochlores R2Ti2O7 ( R=Tb , Dy, and Ho)
Ruminy M., Pomjakushina E., Iida K., Kamazawa K., Adroja D. T., Stuhr U., Fennell T. (2016), Crystal-field parameters of the rare-earth pyrochlores R2Ti2O7 ( R=Tb , Dy, and Ho), in Physical Review B, 94(2), 024430-024430.
First-principles calculation and experimental investigation of lattice dynamics in the rare-earth pyrochlores R2Ti2O7 (R = Tb, Dy, Ho)
Ruminy M., Valdez M. Nunez, Wehinger B., Bosak A., Adroja D. T., Stuhr U., Iida K., Kamazawa K., Pomjakushina E., Prabakharan D., Haas M. K., Bovo L., Sheptyakov D., Cervellino A., Cava R. J., Kenzelmann M., Spaldin N. A., Fennell T. (2016), First-principles calculation and experimental investigation of lattice dynamics in the rare-earth pyrochlores R2Ti2O7 (R = Tb, Dy, Ho), in PHYSICAL REVIEW B, 93(21), 214308.
Sample independence of magnetoelastic excitations in the rare-earth pyrochlore Tb2Ti2O7
Ruminy M., Bovo L., Pomjakushina E., Haas M. K., Stuhr U., Cervellino A., Cava R. J., Kenzelmann M., Fennell T. (2016), Sample independence of magnetoelastic excitations in the rare-earth pyrochlore Tb2Ti2O7, in Physical Review B, 93(14), 144407-144407.
Candidate quantum spin liquid in the Ce3+ pyrochlore stannate Ce2Sn2O7
Sibille Romain, Lhotel Elsa, Pomjakushin Vladimir, Baines Chris, Fennell Tom, Kenzelmann Michel (2015), Candidate quantum spin liquid in the Ce3+ pyrochlore stannate Ce2Sn2O7, in Physical Review Letters, 115, 097202.
Magnetoelastic Excitations in the Pyrochlore Spin Liquid Tb2Ti2O7
Fennell T., Kenzelmann M., Roessli B., Mutka H., Ollivier J., Ruminy M., Stuhr U., Zaharko O., Bovo L., Cervellino A., Haas M. K., Cava R. J. (2014), Magnetoelastic Excitations in the Pyrochlore Spin Liquid Tb2Ti2O7, in PHYSICAL REVIEW LETTERS, 112(1), 017203.
24-spin clusters in the mineral boleite KPb26Ag9Cu24Cl62(OH)48
Dreier E S, Holm S L, Lonbaek K, Hansen U B, Medarde M, Zivkovic I, Babkevich P, Ruminy M, Casati N, Piovano A, Rols S, Nilsen G J, Boehm M, Skoulatos M, Schefer J, Ronnow H M, Fennell T, Lefmann K, 24-spin clusters in the mineral boleite KPb26Ag9Cu24Cl62(OH)48, in Physical Review B, 97, 014416.
Experimental observation of magnetic monopoles in spin ice
Bramwell Steve, Fennell Tom, Experimental observation of magnetic monopoles in spin ice, in Jaubert Ludovic, Udagawa Masafumi (ed.), Springer-Verlag, Heidleberg, 1.
Magnetoelastic effects in rare earth titanate pyrochlores
Ruminy Martin, Magnetoelastic effects in rare earth titanate pyrochlores, ETH, Zurich.

Collaboration

Group / person Country
Types of collaboration
Dr. S. Giblin/Cardiff University Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Prof. V. Tsurkan, Universität Augsburg Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. F. Mila, EPF Lausanne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Prof. P Henelius/KTH Sweden (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Dr. R. Coldea, Oxford Univeristy Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. N. Spaldin/ETHZ, Switzerland Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Prof. S. Bramwell and Dr L Bovo, London Centre for Nanotechnology Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Prof. M. Gingras/University of Waterloo Canada (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
6th European Conference on Neutron Scattering 2015 Talk given at a conference Spin ice physics in the new spinel material CdEr2Se4 30.08.2015 Zaragoza, Spain Gao Shang; Fennell Tom; Rüegg Christian; Zaharko Oksana; Ruminy Martin;
6th European Conference on Neutron Scattering 2015 Talk given at a conference Larmor diffraction study of the R2Ti2O7 series (R=Dy, Ho, Tb) 30.08.2015 Zaragoza, Spain Ruminy Martin; Fennell Tom;
6th European Conference on Neutron Scattering 2015 Poster Spin correlations and magnetoelastic excitations in Tb2Ti2O7 30.08.2015 Zaragoza, Spain Zaharko Oksana; Ruminy Martin; Fennell Tom;
20th International Conference on Magnetism 2015 Poster Spiral-spin‐liquid state in spinel MnSc2S4 05.07.2015 Barcelona, Spain Ruminy Martin; Rüegg Christian; Zaharko Oksana; Gao Shang; Fennell Tom;
20th International Conference on Magnetism 2015 Poster Magnetic field dependence of magnetoelastic interactions in Tb2Ti2O7 05.07.2015 Barcelona, Spain Fennell Tom; Ruminy Martin;
PSI-IOP meeting 2015 Talk given at a conference Emergent monopoles and photons in rare earth pyrochlore magnets 13.05.2015 Windisch, Switzerland Fennell Tom;
American Physical Society March Meeting 2015 Talk given at a conference Magnetoelastic excitations in Tb2Ti2O7 in applied magnetic field 02.03.2015 San Antonio, United States of America Ruminy Martin;
Seminar (HZB) 2015 Individual talk Correlations and excitations in the magnetoelastic spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 19.02.2015 Helmholtz Zentrum Berlin, Germany Fennell Tom;
Workshop on ab initio phonon calculations 2014 Poster The rare earth titanate pyrochlore phonon spectrum 01.12.2014 Krakow, Poland Ruminy Martin;
PSI Summer School 2014 Poster Magnetoelastic modes and quasielastic scattering in Tb2Ti2O7 and Y1.9Tb0.1Ti2O7 11.08.2014 Zuoz, Switzerland Ruminy Martin;
HFM 2014 International Conference on Highly Frustrated Magnetism Talk given at a conference Quasielastic neutron scattering in Tb2Ti2O7 and Y1.9Tb0.1Ti2O7 06.07.2014 Cambridge, Great Britain and Northern Ireland Ruminy Martin; Fennell Tom;
HFM 2014 International Conference on Highly Frustrated Magnetisim Poster Investigation on the low temperature distorted phase of MgCr2O4 06.07.2014 Cambridge, Great Britain and Northern Ireland Fennell Tom; Rüegg Christian; Zaharko Oksana; Gao Shang; Ruminy Martin;
HFM 2014 International Conference on Highly Frustrated Magnetism Poster Spin correlations and magnetoelastic excitations in Tb2Ti2O7 06.07.2014 Cambridge, Great Britain and Northern Ireland Fennell Tom; Ruminy Martin; Zaharko Oksana;
Swiss Physical Society Annual Meeting 2014 Talk given at a conference Quasielastic scattering in Tb2Ti2O7 and Y1.9Tb0.1Ti2O7 30.06.2014 Fribourg, Switzerland Ruminy Martin;
Swiss Physical Society Annual Meeting 2014 Poster Investigation on the low temperature distorted phase of MgCr2O4 30.06.2014 Fribourg, Switzerland Gao Shang;
Workshop on MAGiC: the single crystal diffractometer for magnetism at the ESS 2014 Talk given at a conference Diffuse scattering in rare earth pyrochlores 26.05.2014 Paris, France Fennell Tom;
American Physical Society March Meeting 2014 Talk given at a conference Magnetoelastic excitations in the spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 03.03.2014 Denver, United States of America Fennell Tom;
International Workshop on Frustration and Topology in Condensed Matter Physics 2014 Talk given at a conference (Correlations and) excitations in the magnetoelastic spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 17.02.2014 Tainan, Taiwan Fennell Tom;
Seminar (ISIS) 2013 Individual talk Correlations and excitations in the magnetoelastic spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 12.12.2013 Rutherford Appleton Laboratory, Great Britain and Northern Ireland Fennell Tom;
Mott Physics Beyond the Heisenberg Model 2013 Talk given at a conference Correlations and excitations in the magnetoelastic spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 28.10.2013 Monte Verita, Switzerland Fennell Tom;
International Conference on Neutron Scattering 2013 Poster The magnetoelastic spin liquid Tb2Ti2O7 08.07.2013 Edinburgh, Great Britain and Northern Ireland Ruminy Martin;
International Conference on Neutron Scattering 2013 Talk given at a conference Correlations and excitations in the magnetoelastic spin-liquid state of the rare earth pyrochlore Tb2Ti2O7 08.07.2013 Edinburgh, Great Britain and Northern Ireland Fennell Tom;


Self-organised

Title Date Place
Frontier Experiments with Neutrons 2014 30.06.2014 Fribourg, Switzerland

Awards

Title Year
International Conference on Magnetism, best poster prize 2015

Associated projects

Number Title Start Funding scheme
152734 Spin-liquid and spin-ice states in frustrated rare-earth and transition metal spinels 01.04.2014 SCOPES
129899 Combining d^n (magnetic) and d^0 (lone pair) ions in frustrated low-dimensional magnetic arrangements: a fruitful route for ferroelectricity? 01.10.2010 Project funding
182536 New structures and dynamics emerging from frustration 01.12.2018 Project funding
150713 ZEBRA - a new neutron single-crystal diffractometer optimized for small samples and extreme conditions 01.11.2014 R'EQUIP
117817 Magnetic excitations in novel metal-organic quantum materials and molecular magnets 01.01.2008 Project funding
162626 Frustration in Quantum and Classical Magnets 01.12.2015 Project funding
141962 Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials 01.01.2013 Sinergia
157809 A ultralow background magnet for neutron scattering possibilities under extreme conditions at SINQ 01.10.2015 R'EQUIP
160765 Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials 01.01.2016 Sinergia
144972 High efficiency neutron spectrometer optimized for investigations under extreme conditions 01.01.2014 R'EQUIP

Abstract

We propose a new initiative in frustrated magnetism. Our studies will include investigations of well-developed model systems such as the spin ices, as well as the first studies of new materials using advanced microscopic probes such as neutron and x-ray scattering. Our two projects will investigate systems with different dimensionalities and geometries of the lattice and contrasting classical and quantum spins.Project A focusses on spin and orbital liquid quantum ground states in the frustrated spinel materials ACr2O4 (A= Cr, Mg), CuIr2S4 and ASc2S4 (A=Mn, Fe) with various levels of spin-orbit coupling.Project B investigates the magnetic monopole hopping mechanism in the spin ice materials Ho2Ti2O7 and Dy2Ti2O7. Phonon-assisted tunneling of spins is implicated as a possible mechanism for hopping of monopole excitations.
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