Nuclear magnetic resonance probe head design for precision strain control.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Investigating materials under mechanical strain is crucial for understanding their properties.
• Nuclear Magnetic Resonance (NMR) is a powerful technique for probing local electronic and structural environments.

Purpose of the Study:

• To design and construct a novel NMR probe capable of applying and controlling mechanical strain on single crystals at cryogenic temperatures.
• To demonstrate the probe's capability in revealing strain-induced changes in material properties.

Main Methods:

• Development of a cryogenic NMR probe head featuring a piezoelectric apparatus for strain application.
• Precise control and measurement of both compressive and tensile strain up to 0.3% with 0.001% precision.
• Application of the probe to study 75As NMR in BaFe2As2 single crystals.

Main Results:

• The NMR probe successfully applied tunable strain to single crystals at cryogenic temperatures.
• 75As NMR spectra in BaFe2As2 showed significant changes in the electric field gradient under strain.
• The applied strain was found to be homogeneous within 16% over the NMR coil volume.

Conclusions:

• The developed NMR probe is effective for investigating the effects of mechanical strain on single crystals at low temperatures.
• Strain significantly modifies the electric field gradient in BaFe2As2, providing insights into its electronic structure.
• The probe's precision and homogeneity are suitable for detailed studies of strain-dependent phenomena.