Geometrical frustration, spin ice and negative thermal expansion - the physics of underconstraint

A. P. Ramirez, C. L. Broholm, R. J. Cava, G. R. Kowach

Research output: Contribution to journalConference articlepeer-review

38 Scopus citations


The idea that some systems could have a thermodynamically large number of accessible ground states was presaged in the work of Pauling on ice (Pauling, Cornell University Press, Ithaca, NY, 1945) [1]. With the advent of spin glasses, the methodology for describing ground states changed dramatically, and in particular it was realized that the observed slow dynamics were due to relaxation among a large number of nearly degenerate ground states. Now the accepted wisdom is that both 'frustration', as well as structural disorder, is responsible for spin glass behavior. However, well before spin-glasses were identified as a distinct class of systems, it had been appreciated that even for structurally periodic systems, bond frustration could lead to a thermodynamically large number of states. There is now a well-defined class of magnets which display effects of macroscopic ground state degeneracy. This class of geometrically frustrated magnets presents some new paradigms with which to view condensed matter systems - marginal underconstraint and downward shift of spectral weight. We discuss possible realizations of these phenomena in both in spin ice and also outside the context of local-moment magnetism.

Original languageEnglish (US)
Pages (from-to)290-295
Number of pages6
JournalPhysica B: Condensed Matter
Issue number1-4
StatePublished - May 11 2000
Event22nd International Conference on Low Temperature Physics (LT-22) - Helsinki, Finl
Duration: Aug 4 1999Aug 11 1999

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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