Simultaneous measurements of an ultrasound and a torsional oscillator for 4He in a nanoporous glass

Toshiaki Kobayashi, Junko Taniguchi, Masaru Suzuki, Keiya Shirahama

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Previously, we carried out ultrasonic measurements for liquid 4He filled in a nanoporous glass (Gelsil), and observed an increase in the sound velocity due to decoupling of the superfluid component. At zero pressure, the superfluid transition temperature T C is suppressed to 1.4 K from the bulk lambda point, 2.17 K. This behavior is the same as torsional oscillator measurements by Yamamoto et al. (Phys. Rev. Lett. 93:075302, However, the pressure dependence of T C and the temperature dependence of the superfluid fraction are very different from the torsional oscillator measurements. In order to clarify the origin of the difference, we have developed a new technique of simultaneous measurement of an ultrasound and a torsional oscillator, and the system successfully works for a nanoporous glass. Here, we compare decoupling of the superfluid component for 4He films between an ultrasound and a torsional oscillator.

Original languageEnglish
Pages (from-to)797-801
Number of pages5
JournalJournal of Low Temperature Physics
Volume148
Issue number5-6
DOIs
Publication statusPublished - 2007 Sep 1

Keywords

  • 43.35.Cg
  • 67.40.-w

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics

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