Property of 4He Confined in 1D Nano-porous Medium FSM16 with 2.8-nm Channel Above Bulk Freezing Pressure

We have performed the freezing pressure and heat capacity measurements for 4He confined in a nano-porous medium FSM16 which possesses a one-dimensional 2.8-nm straight channel, in the pressure region above the bulk freezing pressure. At 2.8 MPa, where 4He in the channel remains a non-superfluid liquid down to the lowest temperature, the heat capacity decreases monotonically with decreasing temperature. It is in contrast to the heat capacity at 0.03 MPa with a broad bump at the temperature higher than the superfluid onset. At around the freezing onset in the channel, no clear heat capacity peak was observed. It suggests that the latent heat of the liquid–solid transition in the channel is quite small.