A cryogenic uniaxial strain cell for strain-dependent measurements

We present the design, implementation, and validation of a cryo-compatible uniaxial strain cell for strain-dependent investigations in quantum materials. The cell is actuated by three large-format piezoelectric stacks and achieves maximum sample displacements of about 38 μm at room temperature and 1.7 μm at 5 K. The compact geometry provides an extended mounting area that facilitates the investigation of comparatively large samples and allows flexible contact configurations. The actuators, with a cross-sectional area of 7 × 7 mm$^2$, ensure high mechanical stability and enable the application of substantial forces. A key advantage of the design is the high-resolution capacitive displacement sensor, which enables precise in situ strain control with excellent temporal resolution, allowing for dynamic strain tracking beyond the capabilities of conventional setups. To operate the strain cell over a broad temperature range from 4.2 to 300 K, a modular measurement probe was developed, allowing efficient thermal coupling and integration into cryogenic environments. The functionality and precision of the setup were demonstrated by elastoresistance measurements on the iron-based superconductor BaFe$_2$As$_2$ along the [110] direction. ... mehrThe results were compared to those obtained using the conventional approach, in which the sample is directly glued onto a single piezoelectric actuator, showing excellent agreement in amplitude and temperature dependence of the elastoresistance coefficient. Additional tests revealed that the system remains robust under mechanical vibrations introduced by vacuum pumps, enabling stable operation even with liquid nitrogen cooling. Beyond elastoresistivity, the combination of high mechanical stability and time-resolved strain detection makes the presented setup a versatile platform for a broad range of strain-dependent experiments, including future implementations of thermodynamic techniques such as