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Title: Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2

Abstract

The spin-wave excitations of the geometrically frustrated triangular lattice antiferromagnet CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J1, J2, J3, with J2=J1 0:44 and J3=J1 0:57), as well as out-of-plane coupling (Jz, with Jz=J1 0:29) are required to describe the spin-wave dispersion relations, indicating a three-dimensional character of the magnetic interactions. Two energy dips in the spin-wave dispersion occur at the incommensurate wave vectors associated with multiferroic phase and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.

Authors:
 [1];  [1];  [1];  [2];  [3];  [4]
  1. ORNL
  2. Argonne National Laboratory (ANL)
  3. National Institute of Standards and Technology (NIST)
  4. Osaka University
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
941607
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 99; Journal Issue: 157201
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DISPERSION RELATIONS; NEUTRONS; RESOLUTION; SCATTERING; VECTORS

Citation Formats

Ye, Feng, Fernandez-Baca, Jaime A, Fishman, Randy Scott, Ren, Y., Qiu, Y., and Kimura, T.. Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.99.157201.
Ye, Feng, Fernandez-Baca, Jaime A, Fishman, Randy Scott, Ren, Y., Qiu, Y., & Kimura, T.. Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2. United States. doi:10.1103/PhysRevLett.99.157201.
Ye, Feng, Fernandez-Baca, Jaime A, Fishman, Randy Scott, Ren, Y., Qiu, Y., and Kimura, T.. Mon . "Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2". United States. doi:10.1103/PhysRevLett.99.157201.
@article{osti_941607,
title = {Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2},
author = {Ye, Feng and Fernandez-Baca, Jaime A and Fishman, Randy Scott and Ren, Y. and Qiu, Y. and Kimura, T.},
abstractNote = {The spin-wave excitations of the geometrically frustrated triangular lattice antiferromagnet CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J1, J2, J3, with J2=J1 0:44 and J3=J1 0:57), as well as out-of-plane coupling (Jz, with Jz=J1 0:29) are required to describe the spin-wave dispersion relations, indicating a three-dimensional character of the magnetic interactions. Two energy dips in the spin-wave dispersion occur at the incommensurate wave vectors associated with multiferroic phase and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.},
doi = {10.1103/PhysRevLett.99.157201},
journal = {Physical Review Letters},
number = 157201,
volume = 99,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The spin-wave excitations of the geometrically frustrated triangular lattice antiferromagnet CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J1, J2, J3, with J2/J1{approx}0.44 and J3/J1{approx}0.57), as well as out-of-plane coupling (Jz, with Jz/J1{approx}0.29) are required to describe the spin-wave dispersion relations, indicating a three-dimensional character of the magnetic interactions. Two energy dips in the spin-wave dispersion occur at the incommensurate wave vectors associated with multiferroic phase and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.
  • The spin-wave excitations of the geometrically frustrated triangular lattice antiferromagnet CuFeO{sub 2} have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J{sub 1}, J{sub 2}, J{sub 3}, with J{sub 2}/J{sub 1}{approx_equal}0.44 and J{sub 3}/J{sub 1}{approx_equal}0.57), as well as out-of-plane coupling (J{sub z}, with J{sub z}/J{sub 1}{approx_equal}0.29) are required to describe the spin-wave dispersion relations, indicating a three-dimensional character of the magnetic interactions. Two energy dips in the spin-wave dispersion occur at the incommensurate wave vectors associated with multiferroic phase and can be interpreted as dynamic precursors to the magnetoelectricmore » behavior in this system.« less
  • This paper examines the relation between the spin-wave instabilities of collinear magnetic phases and the resulting non-collinear phases for a geometrically-frustrated triangular-lattice antiferromag- net in the high spin limit. Using a combination of phenomenological and Monte-Carlo techniques, we demonstrate that the instability wave-vector with the strongest intensity in the collinear phase determines the wave-vector of a cycloid or the dominant elastic peak of a more complex non-collinear phase. Our results are related to the observed multi-ferroic phase of Al-doped CuFeO2.
  • While a magnetic phase may be both locally stable and globally unstable, global stability always implies local stability. The distinction between local and global stability is studied on a geometrically-frustrated triangular lattice antiferromagnet with easy axis, single-ion anisotropy D along the z axis. Whereas the critical value Dloc c for local stability may be discontinuous across a phase boundary, the critical value Dglo c Dloc c for global stability must be continuous. We demonstrate this behavior across the phase boundary between collinear 3 and 4 sublattice phases that are stable for large D.
  • The magnetic phase diagram of a geometrically-frustrated triangular-lattice antiferromagnet is evaluated as a function of external magnetic field and anisotropy using a trial spin state built from harmonics of a fundamental ordering wavevector. A non-collinear incommensurate state, observed to be chiral and ferroelectric in CuFeO2, is sandwiched between a collinear state with 4 sublattices (SLs) and a 5-SL state. Chiral and non-collinear 5-SL states are predicted to appear at fields above and below the collinear 5-SL states.