Ultrasonic study on the physical properties of multipoles due to structural chirality and/or geometrical frustration

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K03719
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Hiroshima University
• Principal Investigator: Ishii Isao 広島大学, 先進理工系科学研究科(先), 准教授 (20444713)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 電気四極子 / カイラリティ / 幾何学的フラストレーション

Outline of Final Research Achievements

The physical properties of multipoles due to structural chirality and/or geometrical frustration were investigated by using ultrasonic spectroscopy. In Dy3Ru4Al12 with a distorted kagome lattice, the elastic modulus (quadrupolar susceptibility) shows large hysteresis in the pulsed magnetic-field sweep. There is a possibility that this hysteresis is caused by a quadrupolar glass state due to geometrical frustration. We clarified field-induced ferroquadrupolar states for two different magnetic-field directions in DyNiAl. The electric quadrupole bilinearly couples to a corresponding strain. This result means that two different spontaneous strains emerge depending on the field directions, suggesting a novel multiferroics using switching of the spontaneous strains by the field directions. We also discovered ferroquadrupolar ordering in a magnetically ordered state in ErNiAl, although no quadrupolar ordering occurs in a magnetically ordered state in principle.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

本研究によって，これまでに報告されていない新たな多極子物性の知見が得られた。以下に特筆すべき内容を列挙する。(1)幾何学的フラストレーションに起因した電気四極子グラスの可能性。(2)磁場印可の結晶軸方向によって発生する巨視的な自発歪みをスイッチ出来る新規マルチフェロイクスの可能性。(3)一般的には起こり得ない磁気秩序下での電気四極子秩序の発見。