Dynamic frustrated magnetism inTb2Ti2O7

Unusual field dependence of spin fluctuations on different timescales in Tb2Ti2O7

“…Other measurements of the ac susceptibility have indicated a bifurcation with applied field at low temperature and a frequency dependence consistent with our results. 7,28,30,41 Our data are also in reasonable agreement with other measurements of dM/dH by Legl et al 29 and χ ′ by Yin et al 30 at these temperatures, though the latter study found a subsequent change in the field dependence of χ ′ cooling to 16 mK, accompanied by exceptionally long magnetic relaxation times. The temperature dependence is more pronounced in χ ′′ , where at 68 mK the susceptibility rises to a peak at 15 mT but at ≥ 100 mK it falls monotonically.…”

“…The only theoretical suggestion advanced for features in this field range comes from the quantum spin ice model proposed by Molavian and Gingras 23 , with crossovers between spin arrangements on individual tetrahedra occurring at B * ≈ 16 mT and B c ≈ 82 mT, depending on the effective exchange constant within the model. The energy scheme for these arrangements was argued to be relevant below a temperature of order 1 K, where the spin correlations have developed up to the size of a single tetrahedron, 3,[5][6][7] but the associated partial magnetization plateau predicted in the same work would only be observed well below 0.1 K, perhaps even below 0.02 K, because of the small bandwidth of the lowest lying states. 23 This model has been tested down to 43 mK using bulk magnetization measurements and no evidence for a partial magnetization plateau was found.…”

“…1 In this context the pyrochlore magnet Tb 2 Ti 2 O 7 has proved an intriguing conundrum since no magnetic ordering is observed down to the lowest measured temperature, ∼ 15 mK, far below the Curie-Weiss temperature, Θ CW = −19 K, 2 and on this basis it has been identified as a potential three-dimensional spin liquid. [1][2][3][4][5][6][7] Two alternate theoretical proposals have recently been suggested to account for the lack of observed magnetic ordering in Tb 2 Ti 2 O 7 : the first considers a Jahn-Tellerlike distortion and a two-singlet system coupled by exchange, 8 whilst the second has proposed that quantum fluctuations of the Tb 3+ magnetic moments can renormalize the low-energy effective Hamiltonian of the system from an unfrustrated 111 Ising antiferromagnet to a frustrated 111 Ising ferromagnet. 9 The quantum fluctuation theory is of interest as it suggests Tb 2 Ti 2 O 7 is a quantum analog of the classical spin ice systems Dy 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 , 10,11 a quantum spin ice state.…”

Quadrupole Order in the Frustrated PyrochloreTb2+xTi2−xOTakatsu1, Onoda2, Kittaka3 et al. 2016Phys. Rev. Lett.Self Cite56158901View full textAdd to dashboardCite

“…By increasing the transverse interaction, the system can undergo a phase transition from the U(1) QSL to a long range ordered (LRO) state of transverse spins or pseudospins representing electric-quadrupole moments for non-Kramers ions [9][10][11]. This state can be described as a Higgs phase [16][17][18][19][20].In a quest to QSL states in frustrated magnetic systems from both theoretical [21][22][23] and experimental [24,25] viewpoints, an Ising-like pyrochlore Tb 2 Ti 2 O 7 (TTO) is a potential candidate for a U(1) QSL: it has been reported to remain in a fluctuating spin state down to 50 mK without magnetic LRO [26,27]. However, the origin of this spin liquid state of TTO has been elusive for more than a decade despite many investigations (see Refs.…”

Magnetic correlations in HoxTb2−xTiChang1, Schweika2, Kao3 et al. 2011Phys. Rev. BSelf Cite174140View full textAdd to dashboardCite

“…5,14 Neutron diffraction experiments revealed that the system has developed short-range antiferromagnetic correlations up to temperatures as high as 100 K, 12 which grow very little in range but increase in volume as the system cools. 20 Inelastic neutron scattering and heat-capacity measurements confirmed the first excited and ground states of the system, both doublets, are separated by about 18 K. 14 Heat capacity also reveals a T 2 dependence appropriate of a three-dimensional dynamical system. 5 The excitation partially softens at the first maximum in the magnetic structure factor when spin-spin correlation appears below 20 K (Refs.…”