Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin glass like transition in a highly concentrated Fe-C nanoparticle
  system   A highly concentrated (17 vol.%) Fe-C nano-particle system, with a narrow
size distribution $d = 5.4\pm 0.4$ nm, has been investigated using magnetic ac
susceptibility measurements covering a wide range of frequencies (17 mHz - 170
Hz). A dynamic scaling analysis gives evidence for a phase transition to a low
temperature spin-glass-like phase. The critical exponents associated with the
transition are $z\nu = 10.5 \pm 2$ and $\beta = 1.1 \pm 0.2$. The reason why
the scaling analysis works for this sample, while it may not work for other
samples exhibiting collective behavior as evidenced by aging phenomena, is that
the single particle contribution to $\chi''$ is vanishingly small for $T>T_g$
and hence all slow dynamics is due to collective behavior. This criterion can
only be fulfilled for a highly concentrated nano-particle sample with a narrow
size distribution.

29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio