Temperature and Frequency Dependence of The Sound Velocity in hcp<sup>4</sup>He Crystals

Iwasa, Izumi; Araki, Keisuke; Suzuki, Hideji

doi:10.1143/jpsj.46.1119

Cited by 84 publications

(67 citation statements)

References 11 publications

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“…These mechanically generated kinks travel along the dislocation. Dissipation can take place for example if these are scattered by thermally excited kinks or by thermal phonons [33]. Such a process can define a characteristic velocity v * , such as the crossover velocity seen in figure 6.…”

Section: Velocity Dependence Of the Decoupled Massmentioning

confidence: 99%

On the Mobile Behavior of Solid 4He at High Temperatures

Eyal¹,

Polturak²

2011

J Low Temp Phys

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We report studies of solid helium contained inside a torsional oscillator, at temperatures between 1.07K and 1.87K. We grew single crystals inside the oscillator using commercially pure 4 He and 3 He-4 He mixtures containing 100 ppm 3 He. Crystals were grown at constant temperature and pressure on the melting curve. At the end of the growth, the crystals were disordered, following which they partially decoupled from the oscillator. The fraction of the decoupled He mass was temperature and velocity dependent. Around 1K, the decoupled mass fraction for crystals grown from the mixture reached a limiting value of around 35%. In the case of crystals grown using commercially pure 4 He at temperatures below 1.3K, this fraction was much smaller. This difference could possibly be associated with the roughening transition at the solid-liquid interface.

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Section: Velocity Dependence Of the Decoupled Massmentioning

confidence: 99%

On the Mobile Behavior of Solid 4He at High Temperatures

Eyal¹,

Polturak²

2011

J Low Temp Phys

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“…The network is characterized by the total line density Λ (total dislocation line length per unit volume) and network loop length L N between nodes. From ultrasound measurements of single crystals [20,22,23], it is usually found that 0.1 < ΛL N 2 < 0.2, where Λ ≈ 1 x 10 6 cm −2 and L N ≈ 5 µm. In crystals grown with the BC method it is expected that Λ will increase and L N will decrease.…”

mentioning

confidence: 99%

Effect ofHe3Impurities on the Nonclassical Response to Oscillation of SolidHe4

et al. 2008

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We have investigated the influence of impurities on the possible supersolid transition by systematically enriching isotopically-pure 4 He (< 1 ppb of 3 He) with 3 He. The onset of nonclassical rotational inertia is broadened and shifts monotonically to higher temperature with increasing 3 He concentration, suggesting that the phenomenon is correlated to the condensation of 3 He atoms onto the dislocation network in solid 4 He.

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“…Paalanen et al 57 and Iwasa et al 33,58 show that the dislocation density Therefore, it appears that the grain size in our samples would need to be much smaller than was observed in films in Ref. [59] for the binding of 3 He atoms at grain boundaries to be the cause of the T 1 anomalies we observe.…”

Section: Effect Of Dislocations On Relaxation Timesmentioning

confidence: 59%

NMR investigation of the low-temperature dynamics of solid4He doped with3He impurities

et al. 2013

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The lattice dynamics of solid 4 He has been explored using pulsed NMR methods to study the motion of 3 He impurities in the temperature range where experiments have revealed anomalies attributed to superflow or unexpected viscoelastic properties of the solid 4 He lattice. We report the results of measurements of the nuclear spin-lattice and spin-spin relaxation times that measure the fluctuation spectrum at high and low frequencies, respectively, of the 3 He motion that results from quantum tunneling in the 4 He matrix. The measurements were made for 3 He concentrations 16 < x 3 < 2000 ppm. For 3 He concentrations x 3 = 16 ppm and 24 ppm, large changes are observed for both the spin-lattice relaxation time T 1 and the spin-spin relaxation time T 2 at temperatures close to those for which the anomalies are observed in measurements of torsional oscillator responses and the shear modulus. These changes in the NMR relaxation rates were not observed for higher 3 He concentrations.

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Temperature and Frequency Dependence of The Sound Velocity in hcp⁴He Crystals

Cited by 84 publications

References 11 publications

On the Mobile Behavior of Solid 4He at High Temperatures

On the Mobile Behavior of Solid 4He at High Temperatures

Effect ofHe3Impurities on the Nonclassical Response to Oscillation of SolidHe4

NMR investigation of the low-temperature dynamics of solid4He doped with3He impurities

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Temperature and Frequency Dependence of The Sound Velocity in hcp4He Crystals

Cited by 84 publications

References 11 publications

On the Mobile Behavior of Solid 4He at High Temperatures

On the Mobile Behavior of Solid 4He at High Temperatures

Effect ofHe3Impurities on the Nonclassical Response to Oscillation of SolidHe4

NMR investigation of the low-temperature dynamics of solid4He doped with3He impurities

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Product

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Temperature and Frequency Dependence of The Sound Velocity in hcp⁴He Crystals