We present the first measurement of the thermal boundary conductance, 1/RB, between the U2D2 spin ordered solid and the B superfluid phases of3He. We find that 1/RB is exceedingly high, roughly seven orders of magnitude greater than that between sintered silver powder and liquid3He. For T<0.56 mK, 1/RB appeared to be thermally activated, i.e. 1/RB∼exp(-ε/kBT), with ε=4.5(±0.5) mK, close to the superfluid gap energy. We also present a theory involving magnon-quasiparticle coupling as a model to explain the experimental observations.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Condensed Matter Physics