Magnetic Order in Tetrazolate Kagomé-like Frameworks

Materials with highly frustrated magnetic interactions can host novel states. There are, however, few known hosts for frustrated magnetism, such as the corner-sharing triangular kagome lattice. Metal-organic frameworks (MOFs), built from metal nodes linked by organic linkers, have high structural flexibility so exploration of these should be ideal for uncovering new candidates. Recently high magnetic frustration has been proposed to arise from a kagome lattice in copper and cobalt tetrazolate MOFs. Closer examination of these MOFs suggest, however, that the kagome lattice is one of two interwoven magnetic sublattices and it is unclear how their magnetic frustration is effected by coupling between these. We will determine the ordered magnetic structures of these MOFs and probe for short range order at higher temperatures to establish the origin of their frustrated magnetic interactions.

具有强阻挫磁相互作用的材料可呈现新奇物态。然而，目前已知的阻挫磁性宿主材料寥寥无几，角共享三角笼目晶格（corner-sharing triangular kagome lattice）便是其中典型代表。金属有机框架（Metal-Organic Frameworks，MOFs）由金属节点与有机配体连接构筑而成，具备极高的结构灵活性，因此对这类材料开展研究是发掘新型阻挫磁性候选宿主的理想途径。近期有研究提出，四唑铜与四唑钴金属有机框架中的笼目晶格（kagome lattice）可产生强磁阻挫效应。但对这些MOFs的进一步分析表明，该笼目晶格仅是两个相互交织的磁子晶格之一，目前尚不清楚二者之间的耦合作用会如何影响其磁阻挫特性。本研究将解析这些MOFs的有序磁结构，并在更高温度下探测其短程有序性，以阐明其阻挫磁相互作用的起源。