Anomalous Response of 4He Confined in Nanoporous Media to Torsional Oscillation

The existence of “Non-Classical Rotational Inertia (NCRI)” in solid 4 He below 0.2 K has been controversial and interpreted by a number of different theories. We report on torsional oscillator measurements for 4 He in a nanoporous Gelsil glass, which has a network of nanopores with 3.5 nm in diamete...

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Bibliographic Details
Published in:	Journal of low temperature physics Vol. 169; no. 3-4; pp. 218 - 227
Main Authors:	Yoshimura, Hitomi, Higashino, Rama, Shibayama, Yoshiyuki, Shirahama, Keiya
Format:	Journal Article
Language:	English Japanese
Published:	Boston Springer US 01-11-2012
Subjects:	Characterization and Evaluation of Materials Condensed Matter Physics Magnetic Materials Magnetism Physics Physics and Astronomy Supersolid Helium
Online Access:	Get full text
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Summary:	The existence of “Non-Classical Rotational Inertia (NCRI)” in solid 4 He below 0.2 K has been controversial and interpreted by a number of different theories. We report on torsional oscillator measurements for 4 He in a nanoporous Gelsil glass, which has a network of nanopores with 3.5 nm in diameter. In addition to the usual “low- T NCRI” with an onset temperature 0.15 K, we find a larger decrease in rotational moment of inertia in a broad range of temperature from 0.2 to 1.9 K. This “high- T inertial anomaly” is accompanied with multiple dissipation peaks, but has no dependence on torsional oscillation velocity unlike the low- T NCRI. Since the high- T anomaly is observed also in confined liquid states, it originates in amorphous solid 4 He layer near the pore wall. Our result shows that different types of supersolid—like phenomena, i.e. inertial anomalies, can coexist in a single 4 He sample, even with genuine superfluidity of liquid 4 He.
ISSN:	0022-2291 1573-7357
DOI:	10.1007/s10909-012-0687-3