TY - JOUR
T1 - Observation of non-classical rotational inertia in bulk solid 4He
AU - Kondo, Motoshi
AU - Takada, Shunichi
AU - Shibayama, Yoshiyuki
AU - Shirahama, Keiya
N1 - Funding Information:
Acknowledgements We are grateful to enlightening discussions with Y. Aoki, J. Beamish, M. Chan, E. Kim, H. Kojima, M. Kubota, A. Penzyev, J. Reppy, W. Saslow and M. Suzuki. This work is supported by Grant-in-Aid for Scientific Research on Priority Area “Physics of new quantum phases in superclean materials” (Grant No. 17071010) from The MEXT, Japan.
PY - 2007/9
Y1 - 2007/9
N2 - In recent torsional oscillator experiments by Kim and Chan (KC), a decrease of rotational inertia has been observed in solid 4He in porous materials (Kim, E., Chan, M.H.W. in Nature 427:225, 2004; J. Low Temp. Phys. 138:859, 2005) and in a bulk annular channel (Kim, E., Chan, M.H.W. in Science 305:1941, 2004). This observation strongly suggests the existence of "non-classical rotational inertia" (NCRI), i.e. superflow, in solid 4He. In order to study such a possible "supersolid" phase, we perform torsional oscillator experiments for cylindrical solid 4He samples. We have observed decreases in rotational inertia below 200 mK for two solid samples (pressures P = 4.1 and 3.0 MPa). The observed NCRI fraction at 70 mK is 0.14%, which is about 1/3 of the fraction observed in the annulus by KC. Our observation is the first experimental confirmation of the possible supersolid finding by KC.
AB - In recent torsional oscillator experiments by Kim and Chan (KC), a decrease of rotational inertia has been observed in solid 4He in porous materials (Kim, E., Chan, M.H.W. in Nature 427:225, 2004; J. Low Temp. Phys. 138:859, 2005) and in a bulk annular channel (Kim, E., Chan, M.H.W. in Science 305:1941, 2004). This observation strongly suggests the existence of "non-classical rotational inertia" (NCRI), i.e. superflow, in solid 4He. In order to study such a possible "supersolid" phase, we perform torsional oscillator experiments for cylindrical solid 4He samples. We have observed decreases in rotational inertia below 200 mK for two solid samples (pressures P = 4.1 and 3.0 MPa). The observed NCRI fraction at 70 mK is 0.14%, which is about 1/3 of the fraction observed in the annulus by KC. Our observation is the first experimental confirmation of the possible supersolid finding by KC.
KW - 67.80.-s
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U2 - 10.1007/s10909-007-9471-1
DO - 10.1007/s10909-007-9471-1
M3 - Article
AN - SCOPUS:34547096482
SN - 0022-2291
VL - 148
SP - 695
EP - 699
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
IS - 5-6
ER -