Jan 1, 1978 - The thermal boundary resistance between liquid 3He and copper potassium tutton salt (CPS) was measured in the temperature range of 8.5 ...
JOURNAL DE PHYSIQUE
Colloque C6, supplement au n" 8, Tome 39, aout 1978, page
THERMAL BOUNDARY RESISTANCE BETWEEN LIQUID
3
C6-267
He AND COPPER POTASSIUM TUTTON SALT
Y. Fujii, M. Kubota, H. Matsumoto, Y. Tanaka and T. Shigi
Faculty of Science,
Osaka City University,
Suginoto-Cho,
Svmiyoehi-ku,
Osaka, Japan
Résumé.- Nous avons mesuré la résistance thermique de contact entre 1' He liquide et le sel de tutton de Cuivre et de Potassium (CPS) dans la gamme de température entre 8,5 et 110 mK. Le CPS présente une température de transition (T ) d'apparence ferromagnétique à 29,5 mK. La résistance de contact est proportionnelle à T au-dessus de T et à T - ^ 5 entre T et 15 mK mis à part une singularité à 29,3 mK. Abstract.- The thermal boundary resistance between liquid 3 He and copper potassium tutton salt (CPS) was measured in the temperature range of 8.5 mK to 110 mK. The CPS turned out to have the ferromagnetic-like transition temperature (T ) at 29.5 mK. The boundary resistance was proportional to T above T and to T-1-5 between T and lS mK, except for a sharp dip at 29.3 mK. c c
In 1966 Abel et al. IM found that the ther-
average particle diameter 'V 60 ym) was packed in the
mal boundary resistance between liquid 3 He and CMN
Epibond 100 A case which was inserted into the cell
became smaller below 20 mK than expected from the
by using soap seal. The total amount of liquid 3 He
normal Kapitza resistance. This phenomenon was ex-
(''He concentration less than several ppm) in the
plained as the magnetic coupling between the He nu-
cell was 4.6 cm3. Powdered CMN (9.3 mg) was used to
clear spins and the CMN electron spins. In order to
measure the cell temperature. The 16-Hz susceptibi-
see the behavior of magnetic coupling above and be-
lities of CPS and CMN were measured with an ac mu-
low the magnetic transition temperature of a magne-
tual inductance bridge employing a SQUID as a null
tic salt, we measured the boundary resistance bet-
detector. At first, the temperature dependence of
ween liquid 3 He and copper potassium tutton salt,
16-Hz susceptibility of CPS was measured, which is
CuK., ( 3 0 ^ . 6 ^ 0 , (CPS).
shown in figure 2. The magnetic transition tempera-
The measuring cell made of Stycast 1266 is shown in figure 1. This is thermally connected to
St/ca*t IZic mm
EpLbond 100A
Fig. 1 : Schematic diagram of experimental cell. A : 3He inlet tube. B : Copper brush (thermally connected to mixer). C : Heater. D : CMN. E : Secondary coil (astatic pair). F : Primary coil. G : Lead shield. H : Magnetic field coil. I : CPS. J : Secondary coil (astatic pair). K : Primary coil. L : Soap seal. M : Coil foil hardened with Epibond 100 A (thermally connected to mixer).
Fig. 2
Temperature dependence of the apparent 16_Hz susceptibility (bridge reading) of CPS
ture (T = 29.54 ± 0.15 mK) agrees with the temperature of the specific heat jump (29.5 ± 0.2 mK) measured by M. Rayl 111. Below T
the temperature
variation of the susceptibility becomes small, but one can see a little minimum and maximum as shown in the insertion.
the mixer of a dilution refrigerator by a fine copper wire brush. The specimen of powdered CPS 10.4 mg,
To change the temperature of CPS from the
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19786118
ambient liquid 3 ~ temperature e the dc magnetic field was applied or removed by a superconducting coil wound outside the cell. The time constant for the thermal equilibrium between CPS and liquid 3 ~ was e determined by recording the recovery of the CPS tem-
pond to the strong magnetic coupling effect found by S. Saito /6/ at higher temperatures. However, it is noteworthy that the present anomaly is seen at a very low temperature where liquid 3 ~ degenerates e almost completely.
perature (actually the susceptibility of CPS) to the ambient 3 ~ temperature. e The observed recovery curve seemed to consist of two exponential decays. We think that this effect is due to the thermal resistance of liquid 3He along the narrow channels
References / l / Abel, W.R., Anderson, A.C., Black, W.C. and Wheatley, J.C., Phys. Rev. Lett. 16,273 (1966)
amoung the salt powders. In the case of the powdered sample this effect was not observed because the
121 Rayl, K., Thesis, University of Illinois (1966)
specific heat of CMN is about two orders smaller
/ 3 / Leggett, A . J . and Vuorio, M., 3 . Low Temp. Phys. 3 359 (1970) -
than that of CPS. We adopted the first decay for determining the time constant between liquid 3 ~ and e
/4/ Mills, D.L. and Beal-Monod, M.T., Phys. Rev. @, 343 (1974) /5/ Mills, D.L. and Beal-Monod, M.T., Phys. Rev. @,
CPS.
2473 (1974)
The heat capacity of liquid 3 ~ was e always significantly greater than that of CPS in the present case, so that the time constant
'C
can be con-
nected to the boundary resistance R as T = RCcps. As for the heat capacity of CPS, Ccps, we used the data measured by M. Rayl in the temperature rangeof 20 to 300,mK. The observed temperature dependence QE
the thermal resistance is shown in figure 3 . It is
Fig. 3 : The boundary resistance between liquid 3 ~ e and CPS. The smooth extrapolation of specific heat data by Rayl were used below 20 mK proportional to T above T as expected from the theories / 3 , 4 / , and to ~-5' between T and 15 mK as expected from the theory of Mills et al. 151. But below 15 mK, the temperature dependence of the thermai resistance seems to change to the minus higher power of temperature, if Rayl's data is smoothly extrapolated. At 29.3 mK just below Tc the thermal resistance has a sharp dip of about one third of the normal value. This phenomenon is thought to corres-
/6/
Saito, S., Phys. Rev. Lett. 2, 34 (1977) ; Saito, S., Sato, T., Hanawa, M., Osanai, H. and Nishina, Y., Proc. ULT Hakond Symposium, 309 (1977)
