Current Research

Nanofriction of helium films adsorbed on graphite

quartz crystal with porous gold.

Friction is one of the oldest problems in physics, but the atomic-scale mechanism is understood poorly. We are investigating the sliding fricition of atomically thin helium films adsorbed on graphite by means of the quartz crystal microbalance (QCM) techinique. It was found that the friction of these films decreases at low temperatures and enter the low-friction state.

Nanofriction of fullerene-graphite system

Solid-NMR．

Fullerene-graphite system is a novel material which shows superlubricity. We have been studying the mechanism by measuring its physical properties.

Superfluidity of liquid helium-4 confined in nanoporous materials

simultaneous measurement system of torsional oscillator and ultrasound．

Helium is the second lightest element after hydrogen and the only substance that remains liquid at absolute zero. Helium-4 is one of the isotopes, and its bulk liquid has a phase transition to a superfluid phase at 2.17 K at vapor pressure because of the Bose-Einstein condensate (BEC). It is known that when helium-4 is confined in a porous material, the superfluid transition is suppressed. We are investigating the superfluidity of liquid helium-4 confined in nanoporous materials by means of torsional oscillator and ultrasound techiniqes.

Elastic properties of solids

ultrasound technique．

Elastic properties of solids are sometimes coupled strongly with magnetic ones. We have been measuring elastic properties by means of ultrasound.