Microscopic Investigation of Novel Electronic States by Anharmonic Lattice Vibration and Site-Selective Elemental Substitution with Caged Structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K03544
• 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: University of the Ryukyus
• Principal Investigator: Yogi Mamoru 琉球大学, 理学部, 准教授 (60404555)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 籠状化合物 / 核磁気共鳴 / 核四重極共鳴 / サイト選択的元素置換 / 多極子

Outline of Final Research Achievements

We studied RBe13 and RRu2In2Zn18 (R=rare earth) with caged crystal structures using nuclear magnetic resonance and nuclear quadrupole resonance. We measured the relaxation rate for RBe13 with a nonmagnetic ground state and found that the contribution from anharmonic phonons is absent. For RRu2In2Zn18 (R=La, Pr), In-NQR spectra were measured, and found that In is mainly substituted at the 16c site. Moreover, we found that the crystal electric field ground state of PrRu2In2Zn18 is nonmagnetic Γ3 from 1/T1 measurements. We also found the existence of fluctuations at low temperatures, which may be due to fluctuations caused by higher-order multipoles than quadrupoles.

Free Research Field

固体物性

Academic Significance and Societal Importance of the Research Achievements

本研究では籠構造を持つ化合物について研究を行った。その結果、複数サイトに同一元素を含む化合物についてサイト選択的に元素置換が可能であること、また、どのサイトに置換されたかについて微視的な視点から明らかにすることができた。また、それぞれの籠構造による格子振動の寄与や結晶場基底状態を明らかにし、新たな多極子自由度を有する化合物を見出した。今後、多極子物性の研究がより進むと考えられる。