Anisotropic room temperature magnetism in a novel actinide-based material

The 5f electron orbitals of uranium are extremely unique – with both local and itinerant scenarios resulting in exceptionally unusual electronic structures, a deeper understanding of which can obtained via various spectroscopic tools. The UFe4As2 system is a newly discovered iron-arsenide that contains f elements – one of only three uranium iron arsenides known to date. What is rather uncommon, is that in this material we identify that uranium contributes to magnetism at room temperature, which is not typical for this element given its small energy scales. We thus propose to further investigate this new compound in order to understand its element-specific microscopic magnetic properties and determine how the two magnetic species affect one another. According to magnetization measurements, this anisotropic material should order ferrimagnetically, confirmed by electronic band structure calculations.

铀的5f电子轨道极具特殊性——其同时存在局域（local）与巡游（itinerant）两种电子行为，进而形成极为反常的电子结构，借助各类光谱学手段可实现对该结构的更深入认知。UFe4As2体系是一类新发现的含f区元素的铁砷化物，也是目前已知的仅三种铀铁砷化物之一。颇为罕见的是，本研究在该材料中发现铀在室温下参与了磁性行为——考虑到铀的能量尺度较小，该现象并不符合该元素的常规磁性表现。据此，本研究提议对该新型化合物开展进一步研究，以阐明其元素特异性的微观磁性属性，并厘清两种磁性物种间的相互作用机制。磁化强度测量结果表明，该各向异性材料应呈现亚铁磁有序，该结论已通过电子能带结构计算得到验证。