Finite temperature properties and frustrated ferromagnetism in a square lattice Heisenberg model

N. Shannon, B. Schmidt, K. Penc, P. Thalmeier

Research output: Contribution to journalArticle

109 Citations (Scopus)

Abstract

The spin 1/2 Heisenberg model on a square lattice with antiferromagnetic nearest- and nextnearest neighbour interactions (the J1-J2 model) has long been studied as a paradigm of a two-dimensional frustrated quantum magnet. Only very recently, however, have the first experimental realisations of such systems been synthesized. The newest material, Pb 2VO(PO4)2 seems to have mixed ferro- and antiferromagnetic exchange couplings. In the light of this, we extend the semiclassical treatment of the J1-J2 model to include ferromagnetic interactions, and present an analysis of the finite temperature properties of the model based on the exact diagonalization of 8, 16 and 20 site clusters. We propose that diffuse neutron scattering can be used to resolve the ambiguity inherent in determining the ratio and sign of J1 and J 2 from thermodynamic properties alone, and use a finite temperature Lanczos algorithm to make predictions for the relevant high temperature spin-spin correlation functions. The possibility of a spin-liquid phase occurring for ferromagnetic J1 is also briefly discussed.

Original languageEnglish
Pages (from-to)599-616
Number of pages18
JournalEuropean Physical Journal B
Volume38
Issue number4
Publication statusPublished - Apr 2004

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Ferromagnetism
ferromagnetism
Temperature
Exchange coupling
temperature
Neutron scattering
ambiguity
Magnets
liquid phases
neutron scattering
magnets
Thermodynamic properties
thermodynamic properties
interactions
Liquids
predictions

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Finite temperature properties and frustrated ferromagnetism in a square lattice Heisenberg model. / Shannon, N.; Schmidt, B.; Penc, K.; Thalmeier, P.

In: European Physical Journal B, Vol. 38, No. 4, 04.2004, p. 599-616.

Research output: Contribution to journalArticle

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