Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the question of metallicity and ferromagnetism in charge ordered
  insulating Nd0.5Sr0.5MnO3 nanoparticles   The fascinating phenomenon of destabilization of charge/orbital order in
Nd0.5Sr0.5MnO3 with the reduction of grain size is critically investigated.
Based on our magnetic and transport experiments followed by a theoretical
analysis, we analyze various possible mechanisms and try to delineate a
universal scenario behind this phenomenon. We, revisit this issue and discuss
the overwhelming evidence from experiments on nano and bulk manganites as well
as the absence of correlation between size reduction and pressure effects on
manganites. We propose a phenomenological understanding on the basis of
enhanced surface disorder to explain the appearance of weak ferromagnetism and
metallicity in nanoparticles of Nd0.5Sr0.5MnO3. We also provide supportive
evidence from an ab-initio electron structure calculation and a recent
numerical simulation and argue that the mechanism is universal in all nanosize
charge ordered manganites.

21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex