Exploration of novel hyperkagome antiferromagnets and novel physical properties

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15019
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Kitani Suguru 東京工業大学, 科学技術創成研究院, 助教 (30771828)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 磁気フラストレーション / ハイパーカゴメ格子 / トポケミカル反応 / イオン交換 / 磁性 / 熱容量

Outline of Final Research Achievements

In this study, we aimed to create antiferromagnetic compounds with a hyperkagome lattice, which is a three-dimensional network structure of triangles sharing a vertex, by using topochemical reactions. We have succeeded in synthesizing several new hyperkagome antiferromagnets that exhibit antiferromagnetic phase transitions. Although we did not find the expected novel magnetoelectric effect, we found a peculiar phenomenon that the temperature dependence of the heat capacity in the antiferromagnetic phase is proportional to the square of the temperature in spite of the three-dimensional lattice in all compounds, suggesting the possibility of two-dimensional magnon dispersion in the hyperkagome antiferromagnets.

Free Research Field

物性物理、熱物性

Academic Significance and Societal Importance of the Research Achievements

ハイパーカゴメ格子をもつ反強磁性体という自然には存在しない化合物をトポケミカル反応によって創出することができたことから、同じようにして準安定なフラストレート磁性体をトポケミカル反応を用いて物質開拓を進めることができる道筋を示せた意義は大きい。今回合成した物質では反強磁性相において時間反転対称性の破れは見られなかったことから新奇電気磁気効果は見つけられなかったが、今後さらなる物質開拓により応用的に有用な物性の発見も継続的に目指していく。