Effect of boundary condition on Kapitza resistance between superfluid ${}^3$He-B and sintered metal

Abstract

Understanding the temperature dependence of thermal boundary resistance, or Kapitza resistance, between liquid helium and sintered metal has posed a problem in low temperature physics for decades. In the ballistic regime of superfluid ${}^3$He-B, we find the Kapitza resistance can be described via scattering of thermal excitations (quasiparticles) with a macroscopic geometric area, rather than the sintered metal's microscopic area. We estimate that a quasiparticle needs on the order of 1000 collisions to successfully thermalise with the sinter. Finally, we find that the Kapitza resistance is approximately doubled with the addition of two mono-layers of solid ${}^4$He on the sinter surface, which we attribute to an extra magnetic channel of heat transfer being closed as the non-magnetic solid ${}^4$He replaces the magnetic solid ${}^3$He.

7 pages, 4 figures

References in corpus (1)

• Bolometric calibration of a superfluid ${}^3$He detector for Dark Matter search: direct measurement of the scintillated energy fraction for neutron, electron and muon events