Structural chemistry and magnetic order of the Aurivillius material Bi2CoO2F4

Materials with long range ferroelectric or magnetic order are important for applications including data storage, and a current key research area in functional materials is the design and preparation of materials that combine both these properties. A family of ceramic oxides, the Aurivillius family, are well known for their ferroelectric properties and until now, attempts to introduce magnetic ions into these materials have been limited. In 2018, a new Auriivillius oxide-fluoride, Bi2CoO2F4, was reported. This is exciting because it has long-range magnetic order, and the potential to display ferroelectric properties. Neutron powder diffraction will allow us to investigate its magnetic order, as well as its structural behaviour, helping us understand its properties.

具有长程铁电或磁有序的材料在包括数据存储在内的诸多应用中具有重要价值，而当前功能材料领域的核心研究方向之一，便是设计与制备兼具这两类特性的材料。陶瓷氧化物家族中的奥里维留斯相（Aurivillius）材料以其铁电特性而闻名，截至目前，向这类材料中引入磁性离子的尝试仍较为有限。2018年，首例奥里维留斯型氧氟化物Bi₂CoO₂F₄被报道。该材料的发现令人振奋，因为它不仅具备长程磁有序结构，还拥有呈现铁电特性的潜力。借助中子粉末衍射（neutron powder diffraction）技术，我们可以对其磁有序行为与结构特性展开研究，从而助力我们深入解析该材料的各项性能。