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Abstracts
P4.2
Spontaneous annihilation of topological defects in
3
He-A near T
c
Kasai Jun(1), Okamoto Yohei(1), Nishioka Keishi(1), Takagi Takeo(2), and Sasaki
Yutaka(1)
1) Dept. of Physics, Kyoto University, Kyoto, Japan.
2) Dept. of Applied Physics, University of Fukui, Fukui, Japan.
3) LTM Center, Kyoto University, Kyoto, Japan
We have succeeded in stabilizing a number of textural domain walls inside a single
100 micrometer thickness slab of superfluid
3
He-A. A real space distribution of
those topological defects is observed by our MRI measurements. The locations
and the shapes of topological defects remain the same as far as they are kept
quietly in a deep A phase. However, we found that the topological defects
move and annihilate spontaneously at temperature very near Tc. During the
annealing process there appears a spontaneous change in NMR spectra, which
can be interpreted as spontaneous heat generation. However the relation between
annihilation and heat generation is not clear at this moment.
P4.3
Demagnetisation of Solid
3
He on Aerogel to Study Quasiparticle-Free
Superfluid
Bradley D. I.(1), Fisher S. N.(1), Guenault A. M.(1), Haley R. P.(1), Halperin
W. P.(2), Pickett G. R.(1), Shen Y.(2), Tsepelin V.(1), Vonka J.(1), Zimmerman
A.(2), and Zmeev D. E.(1)
1) Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
2) Department of Physics and Astronomy, Northwestern University, Evanston,
IL 60208, USA
We describe an experimental setup to study both solid and superfluid
3
He at
ultra-low temperatures. A layer of solid
3
He formed on the surface of a large
aerogel sample submersed in superfluid
3
He will be cooled down to below 100
µ
K
in a double nuclear demagnetisation process. NMR on the solid
3
He will be used
to search for the possible magnetic phase transition. Additionally, within the
aerogel sample there is a cavity to create superfluid completely insulated from
all parasitic heat flows. Here we intend to study the Bose-Einstein condensate of
magnons in the state virtually free of quasiparticle excitations. In this contribution
we report the progress made in these experiments.
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