Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Structural Complexity of (Bi0.5Na0.5)TiO3-BaTiO3 as Revealed by
  Raman Spectroscopy   The structural phase diagram of the Pb-free ferroelectric
(Na1/2Bi1/2)1-xBaxTiO3 (NBT-BT), x<0.1, has been explored by Raman spectroscopy
at temperatures from 10 to 470 K. The data provide clear evidence for a
proposed temperature-independent morphotropic phase boundary at x \approx
0.055. However, there is no evidence for a structural phase transition across T
\approx 370 K for x > 0.055, where bulk-property anomalies appear to signal a
transition to a nonpolar or antiferroelectric phase. The results identify that
the phase above 370 K shows short-range ionic displacements that are identical
to those in the long-range-ordered phase below 370 K. These conclusions provide
a natural interpretation of the weak piezoelectric response in this system and
have important implications for the search for Pb-free piezoelectrics.

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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
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The categories of this paper are: econ
31
The categories of this paper are: ao-sci