Demonstration experiments for solid state physics using a table top mechanical Stirling refrigerator

TL;DR

This paper presents simple, educational experiments in solid state physics using a compact Stirling refrigerator, demonstrating phenomena like superconductivity and phase transitions for teaching purposes.

Contribution

It introduces accessible, small-scale cryogenic experiments for educational settings, utilizing a Stirling refrigerator to observe key solid state physics phenomena.

Findings

Observation of magnet levitation over YBCO below critical temperature

Measurement of critical current and temperature of YBCO

Detection of phase transition via ac calorimetry

Abstract

Liquid free cryogenic devices are acquiring importance in basic science and engineering. But they can also lead to improvements in teaching low temperature an solid state physics to graduate students and specialists. Most of the devices are relatively expensive, but small sized equipment is slowly becoming available. Here, we have designed several simple experiments which can be performed using a small Stirling refrigerator. We discuss the measurement of the critical current and temperature of a bulk YBa2Cu3O(7-d) (YBCO) sample, the observation of the levitation of a magnet over a YBCO disk when cooled below the critical temperature and the observation of a phase transition using ac calorimetry. The equipment can be easily handled by students, and also used to teach the principles of liquid free cooling.