Magnetic structure and spin waves in the Kagomé jarosite compoundKFe3(SO4)2(

Abstract

We present a detailed study of the magnetic structure and spin waves in the Fe jarosite compound KFe3(SO4)2(OH)6 for the most general Hamiltonian involving one-and two-spin interactions which are allowed by symmetry. We compare the calculated spin-wave spectrum with the recent neutron scattering data of Matan et al. for various model Hamiltonians which include, in addition to isotropic Heisenberg exchange interactions between nearest (J1) and next-nearest (J2) neighbors, single ion anisotropy and Dzyaloshinskii-Moriya (DM) interactions. We concluded that DM interactions are the dominant anisotropic interaction, which not only fits all the splittings in the spin-wave spectrum but also reproduces the small canting of the spins out of the Kagomé plane. A brief discussion of how representation theory restricts the allowed magnetic structure is also given.

Noncollinear density functional theory having proper invariance and local torque properties

“…Second, materials that display this type of idealized lattice have been realized experimentally. 3,8,10 To the best of our knowledge, the theoretical treatment of these systems has not been attempted with realistic electronic structure Hamiltonians, but rather with models such as the Heisenberg Hamiltonian. [44][45][46][47] Because of the complex chemical environment in real materials, we believe that a fully ab initio treatment, as provided by our formalism, is important in studying such systems.…”

“…In the positive (negative) chirality, the magnetic moments are rotated clockwise (counterclockwise) when each of the triangles is traversed clockwise. 8 These lattices correspond to the classical ground states of the two-dimensional (2D) Heisenberg antiferromagnet with inclusion of interactions beyond the nearest neighbor (nn), which lifts the high degeneracy in the nn models. 49,50 The structure of the lattice is presented in Fig.…”

“…This type of behavior is known and has been observed in, for example, bulk γ -Fe, geometrically spin-frustrated lattices as jarosites, halogen salts of erbium, and surfaces. [3][4][5][6][7][8][9][10] The nontrivial problem of going beyond collinear SDFT to account for spin noncollinearity has been of much recent concern. Even though the extension can be formally derived in terms of the total density and the full magnetization vector, 11 this approach has not yet directly benefited from the knowledge and experience accrued in the development of collinear SDFT functionals.…”

High-field multifrequency ESR in theS=52kagome-lattice antiferromagnet KFe3(OH)Fujita1, Yamaguchi2, Kimura3 et al. 2012Phys. Rev. B200130View full textAdd to dashboardCite

“…Elhajal et al 30 and Yildirim et al 37 is determined by the sign of d z . Accordingly, d z > 0 and d z < 0 stabilize positive and negative chirality, respectively.…”

Polarized neutron scattering studies of the kagomé lattice antiferromagnet

“…The spin-wave calculations of the spin Hamiltonian (Eq. 1) show three branches of low energy spin excitations, which correspond to two out-of-plane excitations and one in-plane excitation [9,10]. By choosing proper orientations of a polarization vector P, which is defined by the direction of a guide field, and wave vector Q, one can distinguish between the in-plane and out-of-plane spin excitations.…”