Development of low-temperature magnetization measurement system for small single crystals

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K18681
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Shibauchi Takasada 東京大学, 大学院新領域創成科学研究科, 教授 (00251356)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 磁化測定 / 希釈冷凍機温度 / 熱力学量 / メンブレン / ファラデー力 / 表面センサー / 磁場勾配 / 微小試料

Outline of Final Research Achievements

In this study, recent micro-electromechanical system (MEMS) device technology is combined with the established Faraday force measurement method to develop a new cryogenic magnetization precision measurement system in micro-sized single-crystal samples. Using a membrane-type surface sensor, we measure the Faraday force generated by magnetization when a magnetic field gradient is applied, by converting the capacitance measurement into the amount of displacement of the membrane. The operation check at room temperature exceeded expectations, but at low temperatures, the gold deposited to form the capacitor caused the membrane to become rigid at low temperatures, revealing points for improvement for the future. In parallel, we developed a high-resolution specific heat measurement system for cryogenic temperatures by combining a dilution refrigerator and a two-axis rotating mechanism, which was fully successful.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

近年、凝縮系物理学分野において、量子相転移やトポロジカル相転移など、絶対零度における物性に関する物理が大きな注目を浴びており、極低温領域における精密物性測定がますます重要となっている。新奇物性を示す可能性のある物質を調べる上で、十分に大きな純良単結晶試料を得ることが困難な場合が往々にしてあり、微小単結晶での精密物性測定の需要は非常に大きい。本研究で開発を目指した極低温領域における磁化や比熱な度の熱力学量の精密測定が微小試料で可能となれば、より広い物質を対象とした極低温熱力学量測定が可能となり、様々な電子相の基底状態の理解が格段に進歩することが期待される。