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Background and Methods of Highly Frustrated Magnetism 2012

Conference Date: 
Dimanche, Juin 3, 2012 (All day)
Scientific Areas: 
Condensed Matter

Perimeter Institute will host a one day school for grad students and post-docs on experimental and theoretical background and methods for the study of Highly Frustrated Magnetic systems. The school will be followed by the International Conference, Highly Frustrated Magnetism 2012, which will be held at McMaster University in Hamilton, Ontario.

Lectures will be given by:

  • Philippe Mendels (Universite de Paris-Sud, France)
  • John Chalker (University of Oxford, UK)
  • Oleg Tchernyshyov (Johns Hopkins University, USA)
  • Collin Broholm (Johns Hopkins University/NIST, USA)
  • Christopher Wiebe (University of Winnipeg, Canada)
  • Xiao-Gang Wen (Perimeter Institute)

For more information regarding the conference, please click here.

 

  • Collin Broholm, John Hopkins University
  • John Chalker, University of Oxford
  • Yong-Baek Kim, University of Toronto
  • Philippe Mendels, University of Paris
  • Oleg Tchernyshyov, John Hopkins University
  • Christopher Wiebe, University of Winnipeg

 

Collin Broholm
Neutron Scattering Techniques for Frustrated Magnetism
Neutron scattering can provide unique atomic scale information about structural and dynamical properties of frustrated magnetism. In this lecture I will give a brief description of theoretical and practical aspects of the technique. Experiments on frustrated magnets that illustrate the capabilities of new instrumentation at the Spallation Neutron Source and NIST will serve as examples. The target audience is scientists who are interested in using neutrons in their research, collaborating with a neutron scattering group, or who seek a deeper understanding of the corresponding experimental literature [1]. 
[1] See http://jins.tennessee.edu/course2012/ for information about an online graduate course to be offered in the fall of 2012 on the use of neutron scattering in quantum condensed matter physics. 
*Work at IQM was supported by the US DoE, office of Basic Energy Sciences, Division of Material Sciences and Engineering under DE-FG02-08ER46544.

John Chalker
Correlations, Fluctuations and Constraints – the Statistical Physics of Classical Models for Geometrically Frustrated Magnets
Theoretical Physics Oxford University 1, Keble Road, Oxford, UK I aim to give a simple overview of the statistical physics of classical models of geometrically frustrated magnets and how this helps us to understand experiments. In particular, I will discuss: (i) how strong frustration promotes strongly fluctuating states; (ii) the Coulomb phase and monopoles in spin-ice; (iii) some effects of disorder in geometrically frustrated magnets.

Yong-Baek Kim
Lightning Review on Quantum Spin Liquid
We provide a brief introduction to quantum spin liquid and review current status of theoretical and experimental progresses on
this subject. Spin liquid phases that arise in different situations are examined in the light of both theoretical models and experimental
systems.

Philippe Mendels
NMR and Frustrated Magnetism
In my tutorial, I’ll review the key-basics of NMR which are necessary to understand the various information that can be extracted from this technique in the context of highly frustrated magnetism up to its limits. Regarding static properties, I’ll emphasize all the power of its local character as compared to macroscopic techniques and will compare NMR to other local techniques such as µSR. I’ll discuss relaxation times as a measurement of dynamics and will introduce quickly filtering factors which are related to the local character of the probe-nucleus and wipe-out effects. How NMR probes frequency and reciprocal space will be discussed and compared to neutrons and muSR. I will finally describe how NMR could reveal some features of impurity / disorder induced (or intrinsic) spin textures in Highly Frustrated Magnets. I’ll sort out which static and dynamical information can be extracted from such NMR measurements and what would be the ideal, still long to go, route in the context of idealized materials with controlled and minute amount of impurities. 
My tutorial will be illustrated by examples from the recent litterature on Cu2+-based kagome lattices, J1-J2 vanadates, NiGa2S4, organic triangular compounds and I will make sure that the key elements needed to understand NMR talks presented at this meeting are reviewed in this tutorial.
Some references:
General introduction and J1-J2 model: P. Carretta and A. Keren, “NMR and µSR in Highly Frustrated Magnets”; P. Mendels and A. Wills “Kagome antiferromagnets: materials versus spin liquid behaviors”,  in Introduction to Highly Frustrated Magnetism”, Eds C. Lacroix, P. Mendels, F. Mila Springer Series in Solid State Sciences, 164
Herbertsmithite: A. Olariu et al., Phys. Rev. Lett.100, 087202 (2008); T. Imai et al. Phys. Rev. B 84, 020411 (2011) ; M. Jeong et al. Phys. Rev. Lett. 107, 237201 (2011)
NiGa2S4 : D. E. MacLaughlin et al., Phys. Rev. B 78, 220403 (2008); Y. Nambu et al. Phys. Rev. B 79, 214108 (2009).
Organic triangular compounds : A. Ardavan and references therein (from Kanoda’s group), J. Phys. Soc. Jpn. 81, 011004 (2012).

Oleg Tchernyshyov
Artificial Spin Ice
Artificial spin ice was invented in 2006 by Peter Schiffer's group as a large-scale model of pyrochlore spin ice. Their system, an array of mesoscopic magnets with submicron dimensions, offered a way to observe the physics of ice rules at the level of individual, albeit large, spins. Today we have artificial magnetic arrays that follow the ice rules almost flawlessly, which makes them better ice models than their natural counterparts. We will highlight both similarities and differences between natural and artificial versions of spin ice. Large differences are expected in the dynamics of these systems. Mesoscopic spins easily transfer energy to internal degrees of freedom. Putting them in motion typically requires driving the system far from equilibrium. Thus, in some aspects, artificial spin ice is closer to granular matter and random magnets than to a regular magnetic solid.

Christopher Wiebe, University of Winnipeg
Quantum Materials Discovery: The Synthesis of Geometrically Frustrated Magnets
TBA

 

Dimanche juin 03, 2012
Speaker(s): 

Neutron scattering can provide unique atomic scale information about structural and dynamical properties of frustrated magnetism. In this lecture I will give a brief description of theoretical and practical aspects of the technique. Experiments on frustrated magnets that illustrate the capabilities of new instrumentation at the Spallation Neutron Source and NIST will serve as examples.

Scientific Areas: 

 

Dimanche juin 03, 2012
Speaker(s): 

We provide a brief introduction to quantum spin liquid and review current status of theoretical and experimental progresses on this subject. Spin liquid phases that arise in different situations are examined in the light of both theoretical models and experimental systems.

 

Dimanche juin 03, 2012
Speaker(s): 

Artificial spin ice was invented in 2006 by Peter Schiffer's group as a large-scale model of pyrochlore spin ice. Their system, an array of mesoscopic magnets with submicron dimensions, offered a way to observe the physics of ice rules at the level of individual, albeit large, spins. Today we have artificial magnetic arrays that follow the ice rules almost flawlessly, which makes them better ice models than their natural counterparts. We will highlight both similarities and differences between natural and artificial versions of spin ice.

 

Dimanche juin 03, 2012
Speaker(s): 

In the last few decades, there has been a marked rise in the diversity of compounds studied with frustrated networks of spins. This was clearly not the case in the early days of this field, where only a handful of “model” systems were being studied (ie.