Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct evidence for the magnetic ordering of Nd ions in NdMn$_2$Si$_2$
  and NdMn$_2$Ge$_2$ by high resolution inelastic neutron scattering   We have investigated the low energy nuclear spin excitations in
NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$ by high resolution inelastic neutron
scattering. Previous neutron diffraction investigations gave ambiguous results
about Nd magnetic ordering at low temperatures. The present element-specific
technique gave direct evidence for the magnetic ordering of Nd ions. We found
considerable difference in the process of the Nd magnetic ordering at low
temperature in NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$. Our results are consistent
with those of magnetization and recent neutron diffraction measurements.

37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
16
The categories of this paper are: stat