High-$T_{C}$ Superconducting Quantum Interference Device Implemented on a Pulsed Tube Cooler for 1 to 50 K Materials Characterization

Here we report the fabrication and electrical characterization of high-transition temperature SQUIDs directly written by helium ion beam irradiation for use in Quantum Design's pulsed tube cooler based physical property measurement system. Our device consists of a SQUID with a direct coupled 300 $\mu$ m diameter flux focusing pickup loop. When DC biased above the critical current, we observe a modulation in the voltage with a peak-to-peak amplitude of 500 $\mu$ V, while having periodicity of 275 nT per flux quantum. The SQUID chip was mounted to the temperature-controlled system equipped with optically aligned piezo scanners which allow the accurate positioning of the sample less than 100 $\mu$ m from the sensor. The system functions as a magnetic properties characterization tool which can operate over a wide temperature range (1–50 K) without thermally isolating the SQUID from the sample.