Spin Correlations in the Geometrically Frustrated RBaCo4O7 Antiferromagnets: Mean-Field Approach and Monte-Carlo Simulations

Abstract

Spin correlations in the geometrically frustrated RBaCo4O7 compounds, usually described as an alternating stacking of Kagome and triangular layers on a hexagonal lattice, have been studied by mean-field approach and by Monte-Carlo simulations. The behavior of the system was modelled with an isotropic Heisenberg Hamiltonian as a function of the relevant parameter Jout/Jin, representing the ratio between exchange integrals inside the Kagome layers, Jin, and between Kagome and triangular layers, Jout. This ratio can be varied in real systems by appropriate chemical substitutions. At the mean-field level, long-range magnetic order with the wave vector at the K-point of symmetry (k=a*/3+b*/3) has been found for Jout/Jin>0.7. Below this value, the dominant Fourier modes are completely degenerate in the entire Brillouin zone. The Monte-Carlo simulations revealed that the long-range ordered configuration found in the mean-field calculations becomes the ground state of the system for Jout/Jin>1.5. Below this critical ratio, quasi one-dimensional magnetic ordering along the c-axis, involving spins of the triangular sublattice was observed. The correlations in the (ab) plane were found to have a short-range 120o character with correlation length dependent on Jout/Jin.

References in corpus (2)

• Competing magnetic interactions in the extended Kagome system YBaCo4O7
• Magnetic Structure of YBaCo4O7 with Kagome- and Triangular-Lattices

Cited by in corpus (11)

• Spin-ordering and magnetoelastic coupling in the extended Kagome system YBaCo4O7
• Identification of a Griffiths singularity in a geometrically frustrated antiferromagnet
• Spin correlations in the extended kagome system YBaCo3FeO7
• Structural, magnetic and electronic properties of CaBaCo4-xMxO7 (M= Fe, Zn)
• Unravelling the complex magnetic structure of multiferroic pyroxene NaFeGe2O6: A combined experimental and theoretical study
• Neutron diffraction study and theoretical analysis of the antiferromagnetic order and diffuse scattering in the layered Kagome system CaBaCo${}_2$Fe${}_2$O${}_7$
• Spin-liquid phase and order-by-disorder of classical Heisenberg spins on the swedenborgite lattice
• The antiferromagnetic Ising model on the swedenborgite lattice
• A possible chiral spin-liquid phase in non-centrosymmetric $R$BaCo${}_4$O${}_7$
• Controlling structural distortion in the geometrically frustrated layered cobaltate YBaCo4O7+δ by Fe substitution and its role on magnetic correlations
• Emergence of a 2d macro-spin liquid in a highly frustrated 3d quantum magnet