Neutron scattering studies of quantum magnets

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• Prof. Bella Lake, Helmholtz Zentrum Berlin
• Friday 07 October 2011, 14:00-15:00
• Physics East 217.

If you have a question about this talk, please contact Elizabeth Blackburn.

Quantum magnetism studies the behaviour of magnetic materials where quantum fluctuations are strong and give rise to exotic behaviours not found in conventional magnets. It is possible to make model materials engineered to exhibit specific quantum features which can then be investigated using neutron scattering. This presentation will discuss a number of different quantum magnets. One of these is KCuF3 which is a one-dimensional, spin-1/2 antiferromagnet which is close to the Luttinger Liquid quantum critical point where quantum fluctuations prevent the development of long-range magnetic order. The excitations are known as spinons and have fractional spin quantum number S=1/2. I will also discuss spin-ladders which consists of two one-dimensional antiferromagnetic spin-1/2 chains (the legs of the ladder) coupled to each other (the rungs of the ladder). Two spin-ladders compounds will be mentioned, first La4Sr10Cu24O41 where the rung coupling is strong and the basic excitations are magnons which have an integer spin quantum number of 1. Secondly CaCu2O3, where the rung coupling is weak and the excitations can be viewed and bound spinons. CaCu2O3 like KCuF3 is also quantum critical and lies close to the Wess-Zumino-Novikov-Witten quantum critical point.

This talk is part of the Condensed Matter Physics Seminars series.

This talk is included in these lists:

• Bham Talks
• Cond. Mat. seminar
• Condensed Matter Physics Seminars
• Physics East 217
• What's on in Physics?

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