Ising versus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi><mml:mi>Y</mml:mi></mml:math>Anisotropy in Frustrated<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>R</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Ti</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="bold">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:math>Compounds as “Seen” by Polarized Neutrons

Cao, Huibo; Gukasov, Arsen; Mirebeau, I.; Bonville, P.; Decorse, Claudia; Dhalenne, G.

doi:10.1103/physrevlett.103.056402

Cited by 121 publications

(211 citation statements)

References 34 publications

(46 reference statements)

Supporting

Mentioning

199

Contrasting

Order By: Relevance

“…As the temperature is lowered down to 6 K, an absorption peak develops around 0.42 THz (1.7 meV). This feature is consistent with the first excited CEF level previously reported by neutron and optical spectroscopic studies [25][26][27][28][29]. A much weaker and so far unreported peak is visible at 0.67 THz (2.78 meV).…”

supporting

confidence: 77%

See 1 more Smart Citation

Double vibronic process in the quantum spin ice candidate Tb2Ti2O7 revealed by terahertz spectroscopy

et al. 2017

Self Cite

View full text Add to dashboard Cite

The origin of quantum fluctuations responsible for the spin liquid state in Tb2Ti2O7 has remained a long standing problem. By synchrotron-based terahertz measurements, we show evidence of strong coupling between the magnetic and lattice degrees of freedom that provides a path to the quantum melting process. As revealed by hybrid crystal electric field-phonon excitations that appear at 0.67 THz below 200 K, and around 0.42 THz below 50 K, the double vibronic process is unique for Tb 3+ in the titanate family due to adequate energy matching and strong quadrupolar moments. The results suggest that lattice motion can indeed be the driving force behind spin flips within the hybridized ground and first excited states, promoting quantum terms in the effective Hamiltonian that describes Tb2Ti2O7.Keywords: THz spectroscopy, pyrochlore, frustration, spin-lattice coupling Over the last decade, spin-ice physics has aroused significant attention [1, 2]. It emerges in pyrochlore magnets, such as Ho 2 Ti 2 O 7 or Dy 2 Ti 2 O 7 , as a result of effective ferromagnetic interactions coupling the Ising-like rare-earth magnetic moments constrained along the local 111 directions by the crystal field [3][4][5] (Fig. 1 (a,b)). This combination impedes long-range order, favoring a disordered and macroscopically degenerate magnetic state governed by an organizing principle, the socalled "ice rule," where two spins point into and two out of each elementary tetrahedron in the structure [3].The possibility that quantum fluctuations can melt the spin ice state is a topical issue. It is expected to lead to a wealth of exotic phenomena such as a quantum superposition of "two-in two-out" configurations and emergent electrodynamics with new deconfined particles [6][7][8][9][10][11].In this context, the puzzling behavior of the spin liquid Tb 2 Ti 2 O 7 has attracted much attention. Despite effective antiferromagnetic interactions, Tb 2 Ti 2 O 7 features no long-range order [12,13], however short-range correlations are present over a broad temperature range [14][15][16]. Remarkably, the ground state supports elastic power law spin correlations [17,18], bearing some resemblance to the pinch point pattern observed in spin ices [19]. Below 300 mK, a dispersing low-energy collective mode is found to emerge from these pinch points, reaching its maximum energy at ∼0.25 meV [20]. This signal likely corresponds to fluctuations between the two |± electronic states of the crystal electric field (CEF) ground state doublet. It was interpreted as a signature of interactions between quadrupoles, highlighting the importance of those degrees of freedom [18,[20][21][22]. This is because the non-Kramers nature of Tb 3+ ions prevents magnetic exchange alone from inducing such fluctuations within the Ising-like ground state [22][23][24].A property that distinguishes Tb 2 Ti 2 O 7 from the other rare-earth titanates is the CEF energy spectrum of Tb 3+ . It features a first excited doublet at a low energy of ∆ ≈ 1.5 meV above the ground state [25][26][27][28][29], ...

show abstract

supporting

confidence: 77%

“…It features a first excited doublet at a low energy of ∆ ≈ 1.5 meV above the ground state [25][26][27][28][29], compared to 25 meV for Ho 3+ in the prototype spin ice compound. Furthermore, below ∼20 K, this excited doublet has been shown to couple to a transverse acoustic phonon, forming a hybrid magneto-elastic excitation [30].…”

mentioning

confidence: 99%

Double vibronic process in the quantum spin ice candidate Tb2Ti2O7 revealed by terahertz spectroscopy

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Measured (symbols) and calculated (solid curve) inverse bulk susceptibility in Tb 2 Ti 2 O 7 single crystal (the disk with the demagnetizing factor N = 1.92). Inset: site susceptibilities measured in [27] (symbols) and calculated single ion susceptibilities in the crystal field (dotted curves 1), renormalized susceptibilities due to dipole-dipole interactions (dotted curves 2) and due to dipole-dipole and anisotropic exchange interactions (solid curves).…”

Section: Resultsmentioning

confidence: 99%

“…Recently, the temperature dependence of the anisotropic site susceptibilities of R 3+ ions in R 2 Ti 2 O 7 (R = Tb, Ho, Er, Yb) were measured using polarized neutron diffraction experiments. These experimental results were interpreted within the framework of a crystal field theory and a mean field approximation by introducing effective anisotropic molecular field tensors [27].…”

Section: Introductionmentioning

confidence: 99%

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores

Малкин¹,

Lummen²,

Loosdrecht³

et al. 2010

J. Phys.: Condens. Matter

116

View full text Add to dashboard Cite

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores Malkin, B. Z.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Dhalenne, G.; Zakirov, A. R. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractThe experimental temperature dependence (T = 2-300 K) of single crystal bulk and site susceptibilities of rare earth titanate pyrochlores R 2 Ti 2 O 7 (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) is analyzed in the framework of crystal field theory and a mean field approximation. Analytical expressions for the site and bulk susceptibilities of the pyrochlore lattice are derived taking into account long range dipole-dipole interactions and anisotropic exchange interactions between the nearest neighbor rare earth ions. The sets of crystal field parameters and anisotropic exchange coupling constants have been determined and their variations along the lanthanide series are discussed.

show abstract

“…[64], and extended to Dy 2 Ti 2 O 7 . The first excited crystal field states are separated by a very large energy gap, so that at low temperatures, the magnetic moments are very well approximated by classical Ising spins pointing in or out of the tetrahedra (see also polarized neutron scattering measurements of the local site susceptibility [65]). …”

Section: Jdn 20mentioning

confidence: 99%

Neutron scattering studies of spin ices and spin liquids

Fennell

2014

Journées de la Neutronique

View full text Add to dashboard Cite

Abstract. In frustrated magnets, competition between interactions, usually due to incompatible lattice and exchange geometries, produces an extensively degenerate manifold of groundstates. Exploration of these states results in a highly correlated and strongly fluctuating cooperative paramagnet, a broad classification which includes phases such as spin liquids and spin ices. Generally, there is no long range order and associated broken symmetry, so quantities typically measured by neutron scattering such as magnetic Bragg peaks and magnon dispersions are absent. Instead, spin correlations characterized by emergent gauge structure and exotic fractional quasiparticles may emerge. Neutron scattering is still an excellent tool for the investigation these phenomena, and this review outlines examples of frustrated magnets on the pyrochlore and kagome lattices with reference to experiments and quantities of interest for neutron scattering. PREAMBLEIn physics, a frustrated system is one in which all interactions cannot be simultaneously minimized, which is also to say that there is competition amongst the interactions. Frustration is most commonly associated with spin systems [1], where its consequences can be particularly well identified, but is by no means limited to magnetism. Frustrated interactions are also relevant in certain structural problems [2][3][4][5][6] Interest in frustrated spin systems stems from the idea that conventional order will be suppressed by the frustration, and an unconventional state will appear in its place. For example, Anderson proposed that in high temperature superconductors, antiferromagnetic Néel ordering would be replaced by a resonating valence bond state (RVB) [17], which would host the superconductivity on doping. If the RVB state could be promoted by enhancing frustration, a route to high(er)-T c materials might appear. This has never been realized, and understanding the character of the "unconventional" states, particularly the quantum spin liquid, which emerge in frustrated magnets is usually the objective of current studies.Extensive reviews of topics in frustrated magnetism can be found in the books edited by Lacroix, Mendels and Mila [1], and by Diep [18]. Topics recently reviewed in the literature include quantum spin liquids [19,20]; various aspects of spin ice [21][22][23]; rare earth pyrochlores [24], spinels [25]; and spin ices and kagome spin liquids have their own chapters in Ref. [1]. In the following, I present a brief This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

show abstract

Ising versusXYAnisotropy in FrustratedR2Ti2O7Compounds as “Seen” by Polarized Neutrons

Cited by 121 publications

References 34 publications

Double vibronic process in the quantum spin ice candidate Tb2Ti2O7 revealed by terahertz spectroscopy

Double vibronic process in the quantum spin ice candidate Tb2Ti2O7 revealed by terahertz spectroscopy

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores

Neutron scattering studies of spin ices and spin liquids

Contact Info

Product

Resources

About