Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Temperature and magnetic field dependence of the lattice constant in
  spin-Peierls cuprate CuGeO_3 studied by capacitance dilatometry in fields up
  to 16 Tesla   We present high resolution measurements of the thermal expansion coefficient
and the magnetostriction along the a-axis of CuGeO_3 in magnetic fields up to
16 Tesla. From the pronounced anomalies of the lattice constant a occurring for
both temperature and field induced phase transitions clear structural
differences between the uniform, dimerized, and incommensurate phases are
established. A precise field temperature phase diagram is derived and compared
in detail with existing theories. Although there is a fair agreement with the
calculations within the Cross Fisher theory, some significant and systematic
deviations are present. In addition, our data yield a high resolution
measurement of the field and temperature dependence of the spontaneous strain
scaling with the spin-Peierls order parameter. Both the zero temperature values
as well as the critical behavior of the order parameter are nearly field
independent in the dimerized phase. A spontaneous strain is also found in the
incommensurate high field phase, which is significantly smaller and shows a
different critical behavior than that in the low field phase. The analysis of
the temperature dependence of the spontaneous strain yields a pronounced field
dependence within the dimerized phase, whereas the temperature dependence of
the incommensurate lattice modulation compares well with that of the
dimerization in zero magnetic field.

27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con