| In this talk I will review recent theoretical results for groundstate and low-temperature thermodynamic properties of highly frustrated quantum antiferromagnets at high magnetic fields. In this high-field region, one can construct exact many-body groundstates in terms of so-called "localized magnons". The localized magnons can be shown to lead to a macroscopic groundstate degeneracy at the saturation field. This degeneracy is reflected by the low-temperature thermodynamic properties. For example, we find an additional low-temperature peak in the specific heat close to the saturation field. Most importantly, the groundstate degeneracy leads to an enhanced magnetocaloric effect which has potential applications for efficient low-temperature cooling. Kagome-type systems are used as an illustration for the general scenario. |
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