1
|
Xie H, Tian L, Chen Q, Sun H, Gao X, Li Z, Mo Z, Shen J. Giant and reversible low field magnetocaloric effect in LiHoF 4 compound. Dalton Trans 2021; 50:17697-17702. [PMID: 34811565 DOI: 10.1039/d1dt02958d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cryogenic refrigeration technology is gradually penetrating into increasing aspects of human life and industrial production. Magnetic refrigeration shows excellent application potential due to its high efficiency, good stability and environmental friendliness. It is important for a magnetic refrigeration system to secure a high-performance magnetocaloric material under a low applied magnetic field, which can greatly simplify the design and reduce the expense. In this study, LiHoF4, a polycrystalline compound prepared by an improved solid-state reaction method undergoes a second-order phase transition below 2 K. Meanwhile, an unexpected giant low-field magnetocaloric effect has been observed. The maximum magnetic entropy changes are 11.0 J kg-1 K-1, 19.0 J kg-1 K-1, and 25.9 J kg-1 K-1 in field changes of 0.6 T, 1.0 T, and 2.0 T, respectively. The giant and reversible low field magnetocaloric effect proves it to be one of the most practical candidates among the cryogenic magnetic refrigerants.
Collapse
Affiliation(s)
- Huicai Xie
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China. .,Jiangxi University of Science and Technology, Ganzhou 341000, People's Republic of China
| | - Lu Tian
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Qi Chen
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Hao Sun
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Xinqiang Gao
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Zhenxing Li
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Zhaojun Mo
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
| | - Jun Shen
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China. .,Jiangxi University of Science and Technology, Ganzhou 341000, People's Republic of China.,Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| |
Collapse
|
2
|
Lehmann J, Bortis A, Derlet PM, Donnelly C, Leo N, Heyderman LJ, Fiebig M. Relation between microscopic interactions and macroscopic properties in ferroics. NATURE NANOTECHNOLOGY 2020; 15:896-900. [PMID: 32958934 DOI: 10.1038/s41565-020-0763-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
The driving force in materials to spontaneously form states with magnetic or electric order is of fundamental importance for basic research and device technology. The macroscopic properties and functionalities of these ferroics depend on the size, distribution and morphology of domains; that is, of regions across which such uniform order is maintained1. Typically, extrinsic factors such as strain profiles, grain size or annealing procedures control the size and shape of the domains2-5, whereas intrinsic parameters are often difficult to extract due to the complexity of a processed material. Here, we achieve this separation by building artificial crystals of planar nanomagnets that are coupled by well-defined, tuneable and competing magnetic interactions6-9. Aside from analysing the domain configurations, we uncover fundamental intrinsic correlations between the microscopic interactions establishing magnetically compensated order and the macroscopic manifestations of these interactions in basic physical properties. Experiment and simulations reveal how competing interactions can be exploited to control ferroic hallmark properties such as the size and morphology of domains, topological properties of domain walls or their thermal mobility.
Collapse
Affiliation(s)
- Jannis Lehmann
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - Amadé Bortis
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - Peter M Derlet
- Condensed Matter Theory Group, Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Claire Donnelly
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Naëmi Leo
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
- Nanomagnetism Group, CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
| | - Manfred Fiebig
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
3
|
Mena M, Hänni N, Ward S, Hirtenlechner E, Bewley R, Hubig C, Schollwöck U, Normand B, Krämer KW, McMorrow DF, Rüegg C. Thermal Control of Spin Excitations in the Coupled Ising-Chain Material RbCoCl_{3}. PHYSICAL REVIEW LETTERS 2020; 124:257201. [PMID: 32639763 DOI: 10.1103/physrevlett.124.257201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
We have used neutron spectroscopy to investigate the spin dynamics of the quantum (S=1/2) antiferromagnetic Ising chains in RbCoCl_{3}. The structure and magnetic interactions in this material conspire to produce two magnetic phase transitions at low temperatures, presenting an ideal opportunity for thermal control of the chain environment. The high-resolution spectra we measure of two-domain-wall excitations therefore characterize precisely both the continuum response of isolated chains and the "Zeeman-ladder" bound states of chains in three different effective staggered fields in one and the same material. We apply an extended Matsubara formalism to obtain a quantitative description of the entire dataset, Monte Carlo simulations to interpret the magnetic order, and finite-temperature density-matrix renormalization-group calculations to fit the spectral features of all three phases.
Collapse
Affiliation(s)
- M Mena
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - N Hänni
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
- Physikalisches Institut, University of Bern, Siedlerstrasse 5, CH-3012 Bern, Switzerland
| | - S Ward
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - E Hirtenlechner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institut Laue Langevin, CS 20156, F-38042 Grenoble, France
| | - R Bewley
- ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - C Hubig
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-University Munich, 80333 München, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - U Schollwöck
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-University Munich, 80333 München, Germany
| | - B Normand
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - K W Krämer
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - D F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ch Rüegg
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva 4, Switzerland
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
- Institute of Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland
| |
Collapse
|
4
|
Chandra P, Lonzarich GG, Rowley SE, Scott JF. Prospects and applications near ferroelectric quantum phase transitions: a key issues review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:112502. [PMID: 28752823 DOI: 10.1088/1361-6633/aa82d2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The emergence of complex and fascinating states of quantum matter in the neighborhood of zero temperature phase transitions suggests that such quantum phenomena should be studied in a variety of settings. Advanced technologies of the future may be fabricated from materials where the cooperative behavior of charge, spin and current can be manipulated at cryogenic temperatures. The progagating lattice dynamics of displacive ferroelectrics make them appealing for the study of quantum critical phenomena that is characterized by both space- and time-dependent quantities. In this key issues article we aim to provide a self-contained overview of ferroelectrics near quantum phase transitions. Unlike most magnetic cases, the ferroelectric quantum critical point can be tuned experimentally to reside at, above or below its upper critical dimension; this feature allows for detailed interplay between experiment and theory using both scaling and self-consistent field models. Empirically the sensitivity of the ferroelectric T c's to external and to chemical pressure gives practical access to a broad range of temperature behavior over several hundreds of Kelvin. Additional degrees of freedom like charge and spin can be added and characterized systematically. Satellite memories, electrocaloric cooling and low-loss phased-array radar are among possible applications of low-temperature ferroelectrics. We end with open questions for future research that include textured polarization states and unusual forms of superconductivity that remain to be understood theoretically.
Collapse
Affiliation(s)
- P Chandra
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, United States of America
| | | | | | | |
Collapse
|
5
|
Horita T, Suwa H, Todo S. Upper and lower critical decay exponents of Ising ferromagnets with long-range interaction. Phys Rev E 2017; 95:012143. [PMID: 28208323 DOI: 10.1103/physreve.95.012143] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Indexed: 11/07/2022]
Abstract
We investigate the universality class of the finite-temperature phase transition of the two-dimensional Ising model with the algebraically decaying ferromagnetic long-range interaction, J_{ij}=|r[over ⃗]_{i}-r[over ⃗]_{j}|^{-(d+σ)}, where d (=2) is the dimension of the system and σ is the decay exponent, by means of the order-N cluster-algorithm Monte Carlo method. In particular, we focus on the upper and lower critical decay exponents, the boundaries between the mean-field-universality, intermediate, and short-range-universality regimes. At the critical decay exponents, it is found that the standard Binder ratio of magnetization at the critical temperature exhibits extremely slow convergence as a function of the system size. We propose more effective physical quantities, namely the combined Binder ratio and the self-combined Binder ratio, both of which cancel the leading finite-size corrections of the conventional Binder ratio. Utilizing these techniques, we clearly demonstrate that in two dimensions, the lower and upper critical decay exponents are σ=1 and 7/4, respectively, contrary to the recent Monte Carlo and renormalization-group studies [M. Picco, arXiv:1207.1018; T. Blanchard et al., Europhys. Lett. 101, 56003 (2013)EULEEJ0295-507510.1209/0295-5075/101/56003].
Collapse
Affiliation(s)
- Toshiki Horita
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Hidemaro Suwa
- Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
| | - Synge Todo
- Department of Physics, University of Tokyo, Tokyo 113-0033, Japan.,Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| |
Collapse
|
6
|
Nag T. Excess energy and decoherence factor of a qubit coupled to a one-dimensional periodically driven spin chain. Phys Rev E 2016; 93:062119. [PMID: 27415220 DOI: 10.1103/physreve.93.062119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Indexed: 06/06/2023]
Abstract
We take a central spin model (CSM), consisting of a one-dimensional environmental Ising spin chain and a single qubit connected globally to all the spins of the environment, to study the excess energy (EE) of the environment and the logarithm of decoherence factor namely, generalized fidelity susceptibility per site (GFSS), associated with the qubit under a periodic driving of the transverse field term of environment across its critical point using the Floquet theory. The coupling to the qubit, prepared in a pure state, with the transverse field of the spin chain yields two sets of EE corresponding to the two species of Floquet operators. In the limit of weak coupling, we derive an approximated expression of GFSS after an infinite number of driving period which can successfully estimate the low- and intermediate-frequency behavior of GFSS obtained numerically with a large number of time periods. Our main focus is to analytically investigate the effect of system-environment coupling strength on the EEs and GFSS and relate the behavior of GFSS to EEs as a function of frequency by plausible analytical arguments. We explicitly show that the low-frequency beatinglike pattern of GFSS is an outcome of two frequencies, causing the oscillations in the two branches of EEs, that are dependent on the coupling strength. In the intermediate frequency regime, dip structure observed in GFSS can be justified by the resonance peaks of EEs at those coupling parameter-dependent frequencies; high-frequency saturation behavior of EEs and GFSS are controlled by the same static Hamiltonian and the associated saturation values are related to the coupling strength.
Collapse
Affiliation(s)
- Tanay Nag
- Department of Physics, Indian Institute of Technology, Kanpur 208 016, India
| |
Collapse
|
7
|
Babkevich P, Jeong M, Matsumoto Y, Kovacevic I, Finco A, Toft-Petersen R, Ritter C, Månsson M, Nakatsuji S, Rønnow HM. Dimensional Reduction in Quantum Dipolar Antiferromagnets. PHYSICAL REVIEW LETTERS 2016; 116:197202. [PMID: 27232040 DOI: 10.1103/physrevlett.116.197202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Indexed: 06/05/2023]
Abstract
We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet LiYbF_{4}. For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent -0.25(1). The exponents agree with the 2D XY/h_{4} universality class despite the lack of apparent two-dimensionality in the structure. The order-parameter exponent for the quantum phase transitions is found to be 0.35(1) corresponding to (2+1)D. These results are in line with those found for LiErF_{4} which has the same crystal structure, but largely different T_{N}, crystal field environment and hyperfine interactions. Our results therefore experimentally establish that the dimensional reduction is universal to quantum dipolar antiferromagnets on a distorted diamond lattice.
Collapse
Affiliation(s)
- P Babkevich
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - M Jeong
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Y Matsumoto
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - I Kovacevic
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A Finco
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- ICFP, Département de physique, École normale supérieure, 45 rue d'Ulm, 75005 Paris, France
| | - R Toft-Petersen
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - C Ritter
- Institut Laue-Langevin, BP 156, F-38042, Grenoble Cedex 9, France
| | - M Månsson
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Department of Materials and Nanophysics, KTH Royal Institute of Technology, SE-164 40 Kista, Sweden
| | - S Nakatsuji
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - H M Rønnow
- Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Féderale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| |
Collapse
|
8
|
Chakraborty S, Vijay A. Effective Hamiltonians for correlated narrow energy band systems and magnetic insulators: Role of spin-orbit interactions in metal-insulator transitions and magnetic phase transitions. J Chem Phys 2016; 144:144107. [PMID: 27083708 DOI: 10.1063/1.4945705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Using a second-quantized many-electron Hamiltonian, we obtain (a) an effective Hamiltonian suitable for materials whose electronic properties are governed by a set of strongly correlated bands in a narrow energy range and (b) an effective spin-only Hamiltonian for magnetic materials. The present Hamiltonians faithfully include phonon and spin-related interactions as well as the external fields to study the electromagnetic response properties of complex materials and they, in appropriate limits, reduce to the model Hamiltonians due to Hubbard and Heisenberg. With the Hamiltonian for narrow-band strongly correlated materials, we show that the spin-orbit interaction provides a mechanism for metal-insulator transition, which is distinct from the Mott-Hubbard (driven by the electron correlation) and the Anderson mechanism (driven by the disorder). Next, with the spin-only Hamiltonian, we demonstrate the spin-orbit interaction to be a reason for the existence of antiferromagnetic phase in materials which are characterized by a positive isotropic spin-exchange energy. This is distinct from the Néel-VanVleck-Anderson paradigm which posits a negative spin-exchange for the existence of antiferromagnetism. We also find that the Néel temperature increases as the absolute value of the spin-orbit coupling increases.
Collapse
Affiliation(s)
- Subrata Chakraborty
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Amrendra Vijay
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
9
|
Local and bulk (13)C hyperpolarization in nitrogen-vacancy-centred diamonds at variable fields and orientations. Nat Commun 2015; 6:8456. [PMID: 26404169 PMCID: PMC4598721 DOI: 10.1038/ncomms9456] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 08/23/2015] [Indexed: 11/30/2022] Open
Abstract
Polarizing nuclear spins is of fundamental importance in biology, chemistry and physics. Methods for hyperpolarizing 13C nuclei from free electrons in bulk usually demand operation at cryogenic temperatures. Room temperature approaches targeting diamonds with nitrogen-vacancy centres could alleviate this need; however, hitherto proposed strategies lack generality as they demand stringent conditions on the strength and/or alignment of the magnetic field. We report here an approach for achieving efficient electron-13C spin-alignment transfers, compatible with a broad range of magnetic field strengths and field orientations with respect to the diamond crystal. This versatility results from combining coherent microwave- and incoherent laser-induced transitions between selected energy states of the coupled electron–nuclear spin manifold. 13C-detected nuclear magnetic resonance experiments demonstrate that this hyperpolarization can be transferred via first-shell or via distant 13Cs throughout the nuclear bulk ensemble. This method opens new perspectives for applications of diamond nitrogen-vacancy centres in nuclear magnetic resonance, and in quantum information processing. Hyperpolarization of nuclear spins for enhancing the sensitivity of magnetic resonance can typically be achieved at low temperatures. Here, the authors demonstrate room-temperature polarization of 13C derived from optically pumped electrons of nitrogen vacancies in diamonds with arbitrary orientations.
Collapse
|
10
|
|
11
|
Álvarez GA, Suter D, Kaiser R. Localization-delocalization transition in the dynamics of dipolar-coupled nuclear spins. Science 2015; 349:846-8. [DOI: 10.1126/science.1261160] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Gonzalo A. Álvarez
- Department of Chemical Physics, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Dieter Suter
- Fakultät Physik, Technische Universität Dortmund, D-44221, Dortmund, Germany
| | - Robin Kaiser
- Institut Non-Linéaire de Nice, CNRS, Université de Nice Sophia Antipolis, 06560, Valbonne, France
| |
Collapse
|
12
|
Bovo L, Bloxsom JA, Prabhakaran D, Aeppli G, Bramwell ST. Brownian motion and quantum dynamics of magnetic monopoles in spin ice. Nat Commun 2013; 4:1535. [PMID: 23443563 PMCID: PMC3586720 DOI: 10.1038/ncomms2551] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/25/2013] [Indexed: 12/03/2022] Open
Abstract
Spin ice illustrates many unusual magnetic properties, including zero point entropy, emergent monopoles and a quasi liquid–gas transition. To reveal the quantum spin dynamics that underpin these phenomena is an experimental challenge. Here we show how crucial information is contained in the frequency dependence of the magnetic susceptibility and in its high frequency or adiabatic limit. The typical response of Dy2Ti2O7 spin ice indicates that monopole diffusion is Brownian but is underpinned by spin tunnelling and is influenced by collective monopole interactions. The adiabatic response reveals evidence of driven monopole plasma oscillations in weak applied field, and unconventional critical behaviour in strong applied field. Our results clarify the origin of the relatively high frequency response in spin ice. They disclose unexpected physics and establish adiabatic susceptibility as a revealing characteristic of exotic spin systems. Isolated magnetic monopoles are usually forbidden, but can arise as quasiparticles in magnetically frustrated spin-ice materials. Bovo et al. explore the classical and quantum natures of these excitations through their influence on the high frequency magnetic susceptibility of dysprosium titanate.
Collapse
Affiliation(s)
- L Bovo
- Department of Physics and Astronomy, London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H OAH, UK.
| | | | | | | | | |
Collapse
|
13
|
Hazzard KRA, Manmana SR, Foss-Feig M, Rey AM. Far-from-equilibrium quantum magnetism with ultracold polar molecules. PHYSICAL REVIEW LETTERS 2013; 110:075301. [PMID: 25166378 DOI: 10.1103/physrevlett.110.075301] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/21/2012] [Indexed: 06/03/2023]
Abstract
Recent theory has indicated how to emulate tunable models of quantum magnetism with ultracold polar molecules. Here we show that present molecule optical lattice experiments can accomplish three crucial goals for quantum emulation, despite currently being well below unit filling and not quantum degenerate. The first is to verify and benchmark the models proposed to describe these systems. The second is to prepare correlated and possibly useful states in well-understood regimes. The third is to explore many-body physics inaccessible to existing theoretical techniques. Our proposal relies on a nonequilibrium protocol that can be viewed either as Ramsey spectroscopy or an interaction quench. The proposal uses only routine experimental tools available in any ultracold molecule experiment. To obtain a global understanding of the behavior, we treat short times pertubatively, develop analytic techniques to treat the Ising interaction limit, and apply a time-dependent density matrix renormalization group to disordered systems with long range interactions.
Collapse
Affiliation(s)
- Kaden R A Hazzard
- JILA, NIST, and Department of Physics, University of Colorado-Boulder, Boulder, Colorado 80309-0440, USA
| | - Salvatore R Manmana
- JILA, NIST, and Department of Physics, University of Colorado-Boulder, Boulder, Colorado 80309-0440, USA
| | - Michael Foss-Feig
- JILA, NIST, and Department of Physics, University of Colorado-Boulder, Boulder, Colorado 80309-0440, USA
| | - Ana Maria Rey
- JILA, NIST, and Department of Physics, University of Colorado-Boulder, Boulder, Colorado 80309-0440, USA
| |
Collapse
|