Development of ultralow-temperature measurement systems by Pomeranchuk cooling

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K18747
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Yamashita Minoru 東京大学, 物性研究所, 准教授 (10464207)
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: 超低温 / 強相関電子物性

Outline of Final Research Achievements

The purpose of this research project is to develop a new cryostat and measurement systems to extend studies of strongly-correlated electron systems down to ultralow temperatures (~1 mK) from a temperature achieved by a commercial cryostat (~50 mK). We have developed a miniature Pomeranchuk cryostat, and have performed the cooling test of the cryostat. Although we could not confirm the lowest temperature of the cryostat owing to some technical issues, improvements required to resolve these issues have been clarified, accomplishing our goal for this project. In addition, we have succeeded measurements of CeCoIn5 down to ultralow temperatures. From the measurements, we revealed a new ordered phase at ultralow temperatures, which has not been obtained by a commercial cryostat. We believe that these results lay the first stone to extend our research of strongly-correlated electron materials down ultralow temperatures.

Free Research Field

低温物理学

Academic Significance and Societal Importance of the Research Achievements

科学研究においてより低温までの研究を行う事は熱揺らぎに隠れていた物質の本質的性質を明らかにするためには必須である。市販の冷凍機で達成可能な温度より低温の超低温領域(~1 mK)での実験には様々な実験的困難があってこれまでほとんど行われてこなかったが、本研究成果はより簡易な方法で超低温を実現するものであり、この温度領域における研究の進展を加速させる結果である。さらに、超低温までのNMR測定からこれまで観測できなかった信号を得ることができ、様々な物質における超低温測定につながる成果である。