Ivko Samuel A, Tustain Katherine, Dolling Tristan, Abdeldaim Aly, Mustonen Otto H J, Manuel Pascal, Wang Chennan, Luetkens Hubertus, Clark Lucy
School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K.
Department of Chemistry and Materials Innovation Factory, University of Liverpool, Liverpool L7 3NY, U.K.
Chem Mater. 2022 Jun 28;34(12):5409-5421. doi: 10.1021/acs.chemmater.2c00289. Epub 2022 Jun 9.
Kagome networks of ferromagnetically or antiferromagnetically coupled magnetic moments represent important models in the pursuit of a diverse array of novel quantum and topological states of matter. Here, we explore a family of Cu-containing metal-organic frameworks (MOFs) bearing kagome layers pillared by ditopic organic linkers with the general formula Cu(CO)()·2ClO (MOF-), where is 1,2-bis(4-pyridyl)ethane (), 1,2-bis(4-pyridyl)ethylene (), or 4,4'-azopyridine (). Despite more than a decade of investigation, the nature of the magnetic exchange interactions in these materials remained unclear, meaning that whether the underlying magnetic model is that of an kagome ferromagnet or antiferromagnet is unknown. Using single-crystal X-ray diffraction, we have developed a chemically intuitive crystal structure for this family of materials. Then, through a combination of magnetic susceptibility, powder neutron diffraction, and muon-spin spectroscopy measurements, we show that the magnetic ground state of this family consists of ferromagnetic kagome layers that are coupled antiferromagnetically via their extended organic pillaring linkers.
铁磁或反铁磁耦合磁矩的 Kagome 网络是探索各种新型量子和拓扑物质状态的重要模型。在此，我们研究了一族含铜的金属有机框架（MOF），其具有由双齿有机连接体支撑的 Kagome 层，通式为 Cu(CO)()·2ClO（MOF-），其中 为 1,2-双（4-吡啶基）乙烷（）、1,2-双（4-吡啶基）乙烯（）或 4,4'-偶氮吡啶（）。尽管经过了十多年的研究，这些材料中磁交换相互作用的本质仍不明确，这意味着其潜在的磁模型是 Kagome 铁磁体还是反铁磁体尚不清楚。利用单晶 X 射线衍射，我们为这一族材料建立了具有化学直观性的晶体结构。然后，通过结合磁化率、粉末中子衍射和μ子自旋光谱测量，我们表明该族材料的磁基态由铁磁 Kagome 层组成，这些层通过其延伸的有机支撑连接体反铁磁耦合。
