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Metamagnetism and soliton excitations in the modulated ferromagnetic Ising chain CoV2O6

Kimber, Simon A. J.; Mutka, Hannu; Chatterji, Tapan; Hofmann, Tommy; Henry, Paul LU ; Bordallo, Heloisa; Argyriou, Dimitri LU and Attfield, J. Paul (2011) In Physical Review B (Condensed Matter and Materials Physics) 84(10).
Abstract
We report a combination of physical property and neutron scattering measurements for polycrystalline samples of the one-dimensional spin-chain compound CoV2O6. Heat capacity measurements show that an effective S = 1/2 state is found at low temperatures and that magnetic fluctuations persist up to similar to 6T(N). Above T-N = 6.3 K, measurements of the magnetic susceptibility as a function of T and H show that the nearest-neighbor exchange is ferromagnetic. In the ordered state, we have discovered a crossover from a metamagnet with strong fluctuations between 5 K and T-N to a state with a 1/3 magnetization plateau at 2 < T < 5 K. We use neutron powder diffraction measurements to show that the antiferromagnetic state has... (More)
We report a combination of physical property and neutron scattering measurements for polycrystalline samples of the one-dimensional spin-chain compound CoV2O6. Heat capacity measurements show that an effective S = 1/2 state is found at low temperatures and that magnetic fluctuations persist up to similar to 6T(N). Above T-N = 6.3 K, measurements of the magnetic susceptibility as a function of T and H show that the nearest-neighbor exchange is ferromagnetic. In the ordered state, we have discovered a crossover from a metamagnet with strong fluctuations between 5 K and T-N to a state with a 1/3 magnetization plateau at 2 < T < 5 K. We use neutron powder diffraction measurements to show that the antiferromagnetic state has incommensurate long-range order and inelastic time-of-flight neutron scattering to examine the magnetic fluctuations as a function of temperature. Above T-N, we find two broad bands between 3.5 and 5 meV and thermally activated low-energy features which correspond to transitions within these bands. These features show that the excitations are deconfined solitons rather than the static spin reversals predicted for a uniform ferromagnetic Ising spin chain. Below T-N, we find a ladder of states due to the confining effect of the internal field. A region of weak confinement below T-N, but above 5 K, is identified which may correspond to a crossover between two- and three-dimensional magnetic ordering. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
84
issue
10
publisher
American Physical Society
external identifiers
  • wos:000294922100004
  • scopus:80053606117
ISSN
1098-0121
DOI
10.1103/PhysRevB.84.104425
language
English
LU publication?
yes
id
80c61363-ef6f-40e4-8e70-16a1803462f6 (old id 2180302)
date added to LUP
2011-10-25 08:54:59
date last changed
2017-10-01 04:00:53
@article{80c61363-ef6f-40e4-8e70-16a1803462f6,
  abstract     = {We report a combination of physical property and neutron scattering measurements for polycrystalline samples of the one-dimensional spin-chain compound CoV2O6. Heat capacity measurements show that an effective S = 1/2 state is found at low temperatures and that magnetic fluctuations persist up to similar to 6T(N). Above T-N = 6.3 K, measurements of the magnetic susceptibility as a function of T and H show that the nearest-neighbor exchange is ferromagnetic. In the ordered state, we have discovered a crossover from a metamagnet with strong fluctuations between 5 K and T-N to a state with a 1/3 magnetization plateau at 2 &lt; T &lt; 5 K. We use neutron powder diffraction measurements to show that the antiferromagnetic state has incommensurate long-range order and inelastic time-of-flight neutron scattering to examine the magnetic fluctuations as a function of temperature. Above T-N, we find two broad bands between 3.5 and 5 meV and thermally activated low-energy features which correspond to transitions within these bands. These features show that the excitations are deconfined solitons rather than the static spin reversals predicted for a uniform ferromagnetic Ising spin chain. Below T-N, we find a ladder of states due to the confining effect of the internal field. A region of weak confinement below T-N, but above 5 K, is identified which may correspond to a crossover between two- and three-dimensional magnetic ordering.},
  articleno    = {104425},
  author       = {Kimber, Simon A. J. and Mutka, Hannu and Chatterji, Tapan and Hofmann, Tommy and Henry, Paul and Bordallo, Heloisa and Argyriou, Dimitri and Attfield, J. Paul},
  issn         = {1098-0121},
  language     = {eng},
  number       = {10},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Metamagnetism and soliton excitations in the modulated ferromagnetic Ising chain CoV2O6},
  url          = {http://dx.doi.org/10.1103/PhysRevB.84.104425},
  volume       = {84},
  year         = {2011},
}