Precise magnetization measurements down to 500 mK using a miniature 3He cryostat and a closed-cycle 3He gas handling system installed in a SQUID magnetometer without continuous-cooling functionality

TL;DR

This paper presents a method for precise magnetization measurements down to 0.5 K using a compact 3He cryostat and a closed-cycle gas handling system integrated with a SQUID magnetometer, enabling detailed low-temperature magnetic studies.

Contribution

The authors developed a miniature 3He cryostat with a closed-cycle gas handling system for SQUID magnetometers, achieving stable measurements at 0.5 K without continuous cooling.

Findings

Successful measurement of the Meissner effect in aluminum below 1 K.

Observation of the lower critical field in CeCoIn5 at 0.5 K.

Stable temperature maintenance for 34 hours at 0.5 K.

Abstract

We have conducted precise magnetization measurements down to 0.5 K with a miniature 3He cryostat and a closed-cycle 3He gas handling system for a commercial superconducting quantum interference device magnetometer [Magnetic Property Measurement System (Quantum Design)]. The gas handling system contains two sorption pumps filled with granular charcoals. We pressurize 3He gas up to ambient pressure for the liquification at 3 K and then pump the vaper for cooling. The lowest sample temperature is ~ 0.5 K and it can persist for 34 hours. We demonstrate the performance of the system by observing the Meissner effect of aluminum below the superconducting transition temperature ~ 1 K. We also measured the magnetization curve of the heavy fermion superconductor CeCoIn5 resulting in successful observation of the lower critical field at 0.5 K.