Interpretation of elastic anomalies in SrTiO3 at 37K

Scott, J. F.; Ledbetter, Hassel

doi:10.1007/s002570050500

Cited by 57 publications

(61 citation statements)

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“…The temperature dependences of the elastic constants of SrTi03 were studied with ultrasonic methods by several authors (Rehwald, 1970;Nes et al, 1992;Scott and Ledbetter, 1997). This work analyses these results in terms of the free energy expansion of Salje ef al.…”

Section: Introductionmentioning

confidence: 97%

Elastic properties of SrTiO₃ crystals at ultralow frequencies

et al. 1999

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The phase transition of SrTiO3 at 105 K has been examined by studying the temperature dependence of the Young's modulus of SrTiO3 crystals along various directions. Dynamic Mechanical Analysis (DMA) at 10-140K and 10-45 Hz has been used for the experiments. The elastic behaviour is interpreted in terms of Landau theory and the DMA results are compared with ultrasonic experiments. The striking differences between the two types of data are attributed to the Occurrence of domain wall motions at low frequencies. These motions are suppressed at high frequencies (ultrasonics). We have studied the temperature behaviour of the low-frequency elastic constants of SrTi03 as function of external stress. The data analysis shows that the domain wall contribution to the elastic constants is essentially suppressed with increasing of uniaxial compression.

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Section: Introductionmentioning

confidence: 97%

Elastic properties of SrTiO₃ crystals at ultralow frequencies

et al. 1999

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“…The perovskite SrTiO 3 has been investigated intensively over many years with regard to its antiferrodistortive structural phase transition and quantum paraelectricity [1,2], not to mention the variety of subtle variations in physical properties of the tetragonal structure and of twin walls within it [3][4][5][6][7][8][9][10][11][12]. Substituting europium for strontium yields an isostructural system, EuTiO 3 , which exhibits closely analogous structural behavior but with the addition of antiferromagnetism below ∼5.5 K [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Elastic and anelastic relaxations associated with phase transitions inEuTiO3

et al. 2014

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Elastic and anelastic properties of single crystal samples of EuTiO 3 have been measured between 10 and 300 K by resonant ultrasound spectroscopy at frequencies in the vicinity of 1 MHz. Softening of the shear elastic constants C 44 and 1 2 (C 11 − C 12 ) by ∼20-30% occurs with falling temperature in a narrow interval through the transition point, T c = 284 K, for the cubic-tetragonal transition. This is accounted for by classical coupling of macroscopic spontaneous strains with the tilt order parameter in the same manner as occurs in SrTiO 3 . A peak in the acoustic loss occurs a few degrees below T c and is interpreted in terms of initially mobile ferroelastic twin walls, which rapidly become pinned with further lowering of temperature. This contrasts with the properties of twin walls in SrTiO 3 , which remain mobile down to at least 15 K. No further anomalies were observed that might be indicative of strain coupling to any additional phase transitions above 10 K. A slight anomaly in the shear elastic constants, independent of frequency and without any associated acoustic loss, was found at ∼140 K. It marks a change from elastic stiffening to softening with falling temperature and perhaps provides evidence for coupling between strain and local fluctuations of dipoles related to the incipient ferroelectric transition. An increase in acoustic loss below ∼80 K is attributed to the development of dynamical magnetic clustering ahead of the known antiferromagnetic ordering transition at ∼5.5 K. Detection of these elastic anomalies serves to emphasize that coupling of strain with tilting, ferroelectric, and magnetic order parameters is likely to be a permeating influence in determining the structure, stability, properties, and behavior of EuTiO 3 .

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“…Bookmark not defined. 2 be narrower than Error! Bookmark not defined.. From this discussion we identify three experimental facts, each invalidating the explanation proposed in [2]:…”

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confidence: 95%

“…As the question is not resolved, all suggestions are worth considering. It is in this spirit that the proposal [1,2] is discussed here. We find that mode crossing (MC) is irrelevant to the BBD and to the anomalies observed in Brillouin scattering from transverse acoustic (TA) modes.…”

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confidence: 98%

“…One of us also pointed out [4], independently from [1], that the anharmonic mixing of modes of different symmetries, probably enhanced by fluctuating paraelectric clusters, may explain violations of selection rules in neutron scattering spectra [5,6]. However, the presentation in [2] mixes up several issues: the broad Brillouin doublet (BBD) [7], the indications for a possible transition at T q [3,4], the unexpected components in neutron spectra [5,6], and the anomalies seen in Brillouin velocities [6,8]. As the question is not resolved, all suggestions are worth considering.…”

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confidence: 99%

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