Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First-principles study on the magnetic properties of ordered
  Nd$_{6}$(Fe,Ga)$_{14}$ alloys   We studied the stable magnetic structure of ordered Nd$_{6}$Fe$_{14-x}$Ga$_x$
($x = 0, 1)$ alloys, which appears in the grain-boundary (GB) phase of Nd-Fe-B
permanent magnets, using first-principles techniques. Slight Ga doping ($x =
1$) was shown to contribute to the stabilization of an anti-ferromagnetic (AF)
state, whereas the non-doped case ($x = 0$) was revealed to favor ferromagnetic
state rather than AF state with a slight energy difference.

26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas