Exploration of non-thermal equilibrium state in manganese oxide

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K14669
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Matsuura Keisuke 国立研究開発法人理化学研究所, 創発物性科学研究センター, 基礎科学特別研究員 (50824017)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 過冷却状態 / 温度掃引速度 / 相競合 / 急冷実験 / 磁化制御 / 強相関電子系 / マンガン酸化物 / 軌道自由度

Outline of Final Research Achievements

In the strongly correlated materials, phase transitions between thermal equilibrium phases have been extensively studied by controlling the environmental parameters such as electric field, magnetic field, pressure and so on. No systematic research in terms of kinetics has been done so far until quite recently. Recently, several strongly correlated materials which shows the metastable electronic state under the rapid cooling have been reported. In this project, we investigate what conditions should be required to realize the supercooling electronic state. The target materials are the colossal magnetoresistive manganites. We have found that close to the phase boundary between charge-orbital-ordered insulating and ferromagnetic metallic phases, the required cooling rate to realize the supercooling rate largely decreases. We have demonstrated that the electronic phase diagram which represents the free-energy landscape is closely related to the cooling rate.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

急冷による準安定状態は、これまで水やガラス、鉄鋼材料など身近な物質においては盛んに研究されてきた。これらは原子レベルの配列に関する話だが、電子レベルでは未解明な点が多かった。これまで電子系においては、急冷下での過冷却準安定状態がどのような条件下で実現されるかは明らかではなく、発見的な物質探索となっていた。本研究課題を通じてその問いに対する答えの一つを提案できたと考えている。また、急冷と徐冷を用いた高速磁化制御などの技術につながることが期待される。