Annealing Effect for Supersolid Fraction in $^4$He
arXiv:cond-mat/0702632 · doi:10.1007/s10909-007-9452-4
Abstract
We report on experimental confirmation of the non-classical rotational inertia (NCRI) in solid helium samples originally reported by Kim and Chan. The onset of NCRI was observed at temperatures below ~400 mK. The ac velocity for initiation of the NCRI suppression is estimated to be ~10 $μ$m/sec. After an additional annealing of the sample at $T= 1.8$ K for 12 hours, ~ 10% relative increase of NCRI fraction was observed. Then after repeated annealing with the same conditions, the NCRI fraction was saturated. It differs from Reppy's observation on a low pressure solid sample.
to be published in J. of Low Temp. Phys. (QFS2006 proceedings)