$^4$He sample probe for combined microwave and dc transport measurements

TL;DR

This paper introduces a custom low-temperature probe capable of combined microwave and dc transport measurements up to 20 GHz, enabling advanced studies of superconductors and nonlinear systems at cryogenic temperatures.

Contribution

The paper presents a novel design of a low-temperature probe with integrated microwave and dc measurement capabilities, including detailed performance analysis and application examples.

Findings

Probe operates from dc to 20 GHz with stable performance.

Enables systematic study of vortex dynamics in superconductors.

Facilitates investigation of nonlinear stochastic systems under combined stimuli.

Abstract

Combined microwave and dc electrical transport measurements at low temperatures represent a valuable experimental method in many research areas. In particular, when samples are conventional superconductors, a typical experiment requires a combination of helium temperatures, a wide range of magnetic fields, and the utilization of coaxial lines along with the usual dc wiring. We report on the general design features and the microwave performance of a custom-made low-temperature sample probe, with a measurement bandwidth tested from dc to 20 GHz. Equipped with 6 coaxial cables, a heater, Hall and temperature sensors, the probe fits into a d32 mm shaft. We present our setup, analyze its microwave performance, and describe two representative experiments enabled by this system. The proposed setup will be essential for a systematic study of the dc and ac response of the vortex dynamics in nanopatterned superconductors subject to combined dc and microwave stimuli. Besides, it will be valuable for the investigation of a broad class of nonlinear stochastic systems where a combination of dc and high-frequency ac driving in a wide temperature range is necessary.