Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Specific heat of unconventional superconductivity in NaxCoO2-yH2O   Comprehensive studies of the low-temperature specific heat C(T,H) in
NaxCoO2-yH2O are presented. At H=0, a very sharp anomaly was observed at T=4.7
K indicating the existence of bulk superconductivity. There exists the T^2 term
in C(T,H=0) in the superconducting state manifesting the line nodal
superconducting order parameter. The superconducting volume fraction is
estimated to be 26.6 % based on the consideration of entropy conservation at Tc
for the second-order superconducting phase transition. An abrupt change of the
slope in Tc(H) was observed. Possible scenarios such as the multiple phase
transitions in the mixed state are discussed.

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The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph