Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High pressure study of the normal and superconducting states of the
  layered pnictide oxide Ba$_{1-x}$Na$_x$Ti$_2$Sb$_2$O with x = 0, 0.10, and
  0.15   Here we present a systematic study of the effects of pressure on the
superconducting and spin/charge density wave (SDW/CDW) transitions of
Ba$_{1-x}$Na$_x$Ti$_2$Sb$_2$O (x = 0, 0.10, and 0.15) by means of resistivity
measurements. For x = 0 and 0.10, external pressure results in a decease of the
SDW/CDW transition temperature T$_c$; however, no measurable change is observed
for the x = 0.15. The pressure effect on the superconducting transition
temperature is different for all three samples. For BaTi$_2$Sb$_2$O (x=0),
T$_c$ increases significantly from 1.2 K at zero pressure to $\sim$ 2.9 K at
16.1 kbars. The 10 % Na-doped sample shows an initial T$_c$ increase up to 4.2
K with pressure which saturates at higher pressure values. For higher Na
concentrations (x=0.15), T$_c$ continuously decreases with increasing pressure.

1
The categories of this paper are: cs
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph