TY - JOUR
T1 - Phase diagram of 4He film in 3D nanopores of ZTC
AU - Nakashima, Yuna
AU - Matsushita, Taku
AU - Hieda, Mitsunori
AU - Wada, Nobuo
AU - Nishihara, Hirotomo
AU - Kyotani, Takashi
N1 - Funding Information:
Acknowledgements We would like to thank T. Kurokawa for technical support. This research was partly supported by Grant-in-Aid for Scientific Research (Grant No. 17071006) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. And, two of authors (T.M. and M.H.) were also supported in part by JSPS Institutional Program for Young Researcher Overseas Visits.
PY - 2011/3
Y1 - 2011/3
N2 - In the study to examine effects of three-dimensional (3D) film connectivity on superfluid 4He film in the pore network, we have measured heat capacities of 4He film adsorbed in zeolite templated carbon (ZTC), which is an assembly of graphene fragments and has network of 1.2 nm pore with the 3D period of 1.4 nm, shorter than those of nanoporous materials studied so far. From the heat of desorption, the 4He film adsorbed in ZTC was observed to be formed up to about 1.4 atomic layers. Heat capacities of the 4He film are rather similar to those on SiO 2-based porous materials than those on graphite, except for large heat capacities of monolayer 4He film. At low coverages, the heat capacity rapidly decreases below a temperature T L, suggesting a localized state of 4He at T<T L. The T L almost monotonically lowers with increasing the coverage. Heat capacity isotherms show maxima around 1.1 layers, which suggests quantum degenerate fluid (Bose fluid) above the coverage. From these results, the phase diagram of 4He film adsorbed in ZTC has been determined.
AB - In the study to examine effects of three-dimensional (3D) film connectivity on superfluid 4He film in the pore network, we have measured heat capacities of 4He film adsorbed in zeolite templated carbon (ZTC), which is an assembly of graphene fragments and has network of 1.2 nm pore with the 3D period of 1.4 nm, shorter than those of nanoporous materials studied so far. From the heat of desorption, the 4He film adsorbed in ZTC was observed to be formed up to about 1.4 atomic layers. Heat capacities of the 4He film are rather similar to those on SiO 2-based porous materials than those on graphite, except for large heat capacities of monolayer 4He film. At low coverages, the heat capacity rapidly decreases below a temperature T L, suggesting a localized state of 4He at T<T L. The T L almost monotonically lowers with increasing the coverage. Heat capacity isotherms show maxima around 1.1 layers, which suggests quantum degenerate fluid (Bose fluid) above the coverage. From these results, the phase diagram of 4He film adsorbed in ZTC has been determined.
KW - 3D nanopores
KW - He film
KW - Phase diagram
KW - Restricted geometry
KW - Zeolite templated carbon (ZTC)
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U2 - 10.1007/s10909-010-0321-1
DO - 10.1007/s10909-010-0321-1
M3 - Article
AN - SCOPUS:79551690071
VL - 162
SP - 565
EP - 572
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
SN - 0022-2291
IS - 5-6
ER -