Temperature-dependent Raman study of the spin-liquid pyrochlore<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Tb</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mtext>Ti</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math>

Mączka, Mirosław; Sanjuán, M. L.; Fuentes, Antonio F.; Hermanowicz, K.; Hanuza, J.

doi:10.1103/physrevb.78.134420

Cited by 57 publications

(70 citation statements)

References 44 publications

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“…32 The existence of magnetoelastic modes was suggested as an explanation for why frustration is not relieved in TTO by any conventional symmetry-breaking transitions at low temperatures.…”

Section: Discussionmentioning

confidence: 99%

Crystal field states ofTb3+in the pyrochlore spin liquidTb2Ti2O7<

et al. 2015

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We report time-of-flight neutron scattering measurements of the magnetic spectrum of Tb 3+ in Tb2Ti2O7. The data, which extend up to 120 meV and have calibrated intensity, enable us to consolidate and extend previous studies of the single-ion crystal field spectrum. We successfully refine a model for the crystal field potential in Tb2Ti2O7 without relying on data from other rare earth titanate pyrochlores, and we confirm that the ground state is a non-Kramers doublet with predominantly | ± 4 components. We compare the model critically with earlier models.

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“…32 The existence of magnetoelastic modes was suggested as an explanation for why frustration is not relieved in TTO by any conventional symmetry-breaking transitions at low temperatures.…”

Section: Discussionmentioning

confidence: 99%

Crystal field states ofTb3+in the pyrochlore spin liquidTb2Ti2O7<

et al. 2015

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“…According to definition (6), in this case λ = λ ⊥,1 = λ ⊥,2 = λ is , and the exchange coupling constant equals J = (2µ B ) 2 λ is . For the sample studied, the calculated dipolar contribution θ W,dip into the Weiss temperature equals −0.763 K, and thus the exchange contribution equals θ W,ex = θ W − θ W,dip = −9.537 K. [38].…”

Section: Discussionmentioning

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

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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.

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“…In [15], the scheme of energy levels of Tb 3+ ions in Tb 2 Ti 2 O 7 was constructed assuming that the ground multiplet 7 F 6 does not contain sublevels in the energy range of 160-320 cm -1 (however, the authors of [18] observed a low intensity line in the spectrum of inelastic neutron scattering that corresponded to the excitation energy of 260 cm -1 , the authors of [25] observed a line in the Raman spectrum with an energy of 284 cm -1 , which was attributed to the electronic excitation, and, in [15,18], an intense line with an energy of 270 cm -1 was observed in the spectrum of inelastic neutron scattering in the isostructural compound Tb 2 Sn 2 O 7 ), but there are two close sublevels in the energy range of 115-135 cm -1 . Indeed, in this energy range, the spectra of inelastic neutron scattering [15,18,23] and Raman light scattering [24] contain a line with a doublet structure (note that, in [23], the excitation energy of 130 cm -1 was attributed to optical lattice vibrations).…”

Section: Parameters Of the Crystal Fieldmentioning

confidence: 99%

“…Information on the structure of the energy spectrum of Tb 3+ ions in Tb 2 Ti 2 O 7 crystals (Table 2) was obtained from measurements of the static magnetic susceptibility and thermal capacity [7,16,22], investigations of spectra of inelastic neutron scattering [15,16,18,23] and Raman light scattering [24,25]. Differences between sets of parameters of the crystal field that are available from the literature (Table 3) are partially caused by the fact that the authors of [7,15,18,20] considered operator (2) of the ion energy in the crystal field in terms of a truncated basis set of 13 states of the ground multiplet 7 F 6 .…”

Section: Parameters Of the Crystal Fieldmentioning

confidence: 99%

Crystal field and magnetoelastic interactions in Tb2Ti2O7

Klekovkina

Малкин

2014

Opt. Spectrosc.

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Abstract-In terms of a semi-phenomenological exchange charge model, we have obtained estimates of parameters of the crystal field and parameters of the electron-deformation interaction in terbium titanate Tb 2 Ti 2 O 7 with a pyrochlore structure. The obtained set of parameters has been refined based on the analysis of spectra of neutron inelastic scattering and Raman light scattering, field dependences of the forced magnetostriction, and temperature dependences of elastic constants. INTRODUCTIONInterest in investigations of rare-earth (RE) crystals with a pyrochlore structure (rare-earth ions form a three-dimensional network of tetrahedra with connected vertices) is mainly determined by the wide diversity of magnetic behavior that they exhibit at low temperatures [1]. Among titanates RE 2 Ti 2 O 7 , of most interest is terbium titanate Tb 2 Ti 2 O 7 , in which the magnetic long-range order does not manifest itself at least to a temperature of 15 mK [2], whereas, in accordance with calculations, the phase transition from the paramagnetic to an antiferromagnetic state should have occurred at a temperature of 1.8 K [3]. Interestingly, an external pressure induces a long-range magnetic order in Tb 2 Ti 2 O 7 : under a pressure of 8.6 GPa at temperatures below 2.1 K, apart from the spin-liquid phase, an antiferromagnetic order with a complex magnetic structure is observed [4,5].It is known that magnetoelastic interactions can strongly affect the magnetic behavior of rare-earth compounds. In terbium titanate single crystals and powders, an anomalously large parastriction (deformation of the lattice in the paramagnetic phase in an external magnetic field) has been revealed, which achieves values of ~10 -4 in magnetic fields ~1 T at liquid-helium temperatures [6][7][8]. The parastriction of isostructural crystals Dy 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 under the same conditions acquires values that are typical for paramagnets (~10 -6 ) [9]. In addition, in Tb 2 Ti 2 O 7 , an anomalous decrease in the Young modulus and elastic constants upon lowering temperature was revealed [10][11][12][13]. The cooperative Jahn-Teller effect (spontaneous symmetry violation caused by interactions of rare-earth ions via fields of static and dynamic deformations) can suppress the magnetic ordering. In [10], the temperature of a possible structural phase transition was estimated to be c T  0.1 K. Previously, using a semi-phenomenological model of the crystal field, we have calculated parameters that characterize changes in the crystal field caused by macroscopic deformations of the lattice [14]. The change in the elasticity modulus C 44 of Tb 2 Ti 2 O 7 crystals in the temperature range of 100-4.2 K calculated with this set of parameters is consistent with measurement data. However, the change in elasticity modulus 11

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Temperature-dependent Raman study of the spin-liquid pyrochloreTb2Ti2O7

Cited by 57 publications

References 44 publications

Crystal field states ofTb3+in the pyrochlore spin liquidTb2Ti2O7<

Crystal field states ofTb3+in the pyrochlore spin liquidTb2Ti2O7<

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

Crystal field and magnetoelastic interactions in Tb2Ti2O7

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