Nuclear Magnetic Resonance Probe Head Design for Precision Strain Control

TL;DR

This paper introduces a specialized NMR probe head capable of applying precise strain to single crystals at cryogenic temperatures, enabling detailed studies of strain effects on material properties.

Contribution

The design integrates a piezoelectric apparatus for controlled strain tuning in NMR experiments at cryogenic temperatures, with demonstrated homogeneity and high precision.

Findings

Strain tuning up to 0.3% with 0.001% precision

Homogeneous strain distribution within 16% over the NMR coil volume

Significant changes in electric field gradient observed in BaFe₂As₂

Abstract

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.