Abstract
We report measurements of elastic moduli of hcp solid He4 down to 15 mK when the samples are rotated unidirectionally. Recent investigations have revealed that the elastic behavior of solid He4 is dominated by gliding of dislocations and pinning of them by He3 impurities, which move in the solidlike Bloch waves (impuritons). Motivated by the recent controversy of torsional oscillator studies, we have performed direct measurements of shear and Young's moduli of annular solid He4 using pairs of quarter-circle-shape piezoelectric transducers (PZTs) while the whole apparatus is rotated with angular velocity Ω up to 4 rad/s. We have found that shear modulus μ is suppressed by rotation below 80 mK, when shear strain applied by PZT exceeds a critical value, above which μ decreases because the shear strain unbinds dislocations from He3 impurities. The rotation-induced decrement of μ at Ω=4 rad/s is about 14.7(12.3)% of the total change of temperature dependent μ for solid samples of pressure 3.6(5.4) MPa. The decrements indicate that the probability of pinning of He3 on dislocation segment G decreases by several orders of magnitude. We propose that the motion of He3 impuritons under rotation becomes strongly anisotropic by the Coriolis force, resulting a decrease in G for dislocation lines aligning parallel to the rotation axis.
| Original language | English |
|---|---|
| Article number | 054516 |
| Journal | Physical Review B |
| Volume | 97 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2018 Feb 23 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
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Effect of rotation on the elastic moduli of solid He 4. / Tsuiki, T.; Takahashi, D.; Murakawa, S.; Okuda, Y.; Kono, K.; Shirahama, Keiya.
In: Physical Review B, Vol. 97, No. 5, 054516, 23.02.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of rotation on the elastic moduli of solid He 4
AU - Tsuiki, T.
AU - Takahashi, D.
AU - Murakawa, S.
AU - Okuda, Y.
AU - Kono, K.
AU - Shirahama, Keiya
PY - 2018/2/23
Y1 - 2018/2/23
N2 - We report measurements of elastic moduli of hcp solid He4 down to 15 mK when the samples are rotated unidirectionally. Recent investigations have revealed that the elastic behavior of solid He4 is dominated by gliding of dislocations and pinning of them by He3 impurities, which move in the solidlike Bloch waves (impuritons). Motivated by the recent controversy of torsional oscillator studies, we have performed direct measurements of shear and Young's moduli of annular solid He4 using pairs of quarter-circle-shape piezoelectric transducers (PZTs) while the whole apparatus is rotated with angular velocity Ω up to 4 rad/s. We have found that shear modulus μ is suppressed by rotation below 80 mK, when shear strain applied by PZT exceeds a critical value, above which μ decreases because the shear strain unbinds dislocations from He3 impurities. The rotation-induced decrement of μ at Ω=4 rad/s is about 14.7(12.3)% of the total change of temperature dependent μ for solid samples of pressure 3.6(5.4) MPa. The decrements indicate that the probability of pinning of He3 on dislocation segment G decreases by several orders of magnitude. We propose that the motion of He3 impuritons under rotation becomes strongly anisotropic by the Coriolis force, resulting a decrease in G for dislocation lines aligning parallel to the rotation axis.
AB - We report measurements of elastic moduli of hcp solid He4 down to 15 mK when the samples are rotated unidirectionally. Recent investigations have revealed that the elastic behavior of solid He4 is dominated by gliding of dislocations and pinning of them by He3 impurities, which move in the solidlike Bloch waves (impuritons). Motivated by the recent controversy of torsional oscillator studies, we have performed direct measurements of shear and Young's moduli of annular solid He4 using pairs of quarter-circle-shape piezoelectric transducers (PZTs) while the whole apparatus is rotated with angular velocity Ω up to 4 rad/s. We have found that shear modulus μ is suppressed by rotation below 80 mK, when shear strain applied by PZT exceeds a critical value, above which μ decreases because the shear strain unbinds dislocations from He3 impurities. The rotation-induced decrement of μ at Ω=4 rad/s is about 14.7(12.3)% of the total change of temperature dependent μ for solid samples of pressure 3.6(5.4) MPa. The decrements indicate that the probability of pinning of He3 on dislocation segment G decreases by several orders of magnitude. We propose that the motion of He3 impuritons under rotation becomes strongly anisotropic by the Coriolis force, resulting a decrease in G for dislocation lines aligning parallel to the rotation axis.
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U2 - 10.1103/PhysRevB.97.054516
DO - 10.1103/PhysRevB.97.054516
M3 - Article
VL - 97
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 2469-9950
IS - 5
M1 - 054516
ER -