Magnetic thermal-boundary resistance between enhanced nuclear spin systems and liquid 3He

The Kapitza resistance between TmVO4 and liquid 3He in the temperature range 1-40 mK was measured. The Kapitza resistance was proportional to T2 below about 3 mK. By adding a small amount of 4He, the Kapitza resistance was enlarged. Applying magnetic fields up to about 70 Oe, the resistance also increased. The decreasing Kapitza resistivity with decreasing temperature was also observed between HoVO4 and liquid 3He. Its value, however, was two orders of magnitude smaller than that for TmVO4. The experimental results can be explained by the magnetic coupling between enhanced nuclear spins of Tm or Ho and nuclear spins of adsorbed solid 3He on the surface of the crystal. By using this model numerical calculation of the Kapitza resistivity was made