Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nuclear Magnetic Resonance Probe Head Design for Precision Strain
  Control   We present the design and construction of an NMR probe to investigate single
crystals under strain at cryogenic temperatures. The probe head incorporates a
piezoelectric-based apparatus from Razorbill Instruments that enables both
compressive and tensile strain tuning up to strain values on the order of 0.3%
with a precision of 0.001%. $^{75}$As NMR in BaFe$_2$As$_2$ reveals large
changes to the electric field gradient, and indicates that the strain is
homogeneous to within 16% over the volume of the NMR coil.

14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph