论文标题
单个磁石中晶的磁各向异性
Magnetic anisotropy of individual maghemite mesocrystals
论文作者
论文摘要
对创建磁性超材料的兴趣导致了磁性纳米颗粒上层建筑的方法。 Maghemite（$γ\ text {-fe} _2 \ text {o} _3 $）纳米颗粒的介质晶体可以被布置到高度有序的身体以身体为中心的四方晶格中。尽管已经对无序集合的测量进行了测量，但由于其较小的总磁矩，确定单个介质晶体的磁性具有挑战性。在这里，我们通过利用敏感的动态悬臂磁力计来克服这些挑战，以研究单个微米大小的$γ\ text {-fe} _2 \ text {o} _3 $中晶。这些测量结果揭示了明确的立方各向异性，这是由组成型岩岩纳米颗粒的结晶各向异性及其在介质晶格中的比对。各向异性及其Orgins的特征之所以亮起，是因为我们将高度有序的中晶的自组装与解决其个体磁性的能力相结合。这种组合对于对其他纳米颗粒的磁各向异性的未来研究很有希望，这些纳米颗粒的磁各向异性太小而无法单独研究。
Interest in creating magnetic metamaterials has led to methods for growing superstructures of magnetic nanoparticles. Mesoscopic crystals of maghemite ($γ\text{-Fe}_2\text{O}_3$) nanoparticles can be arranged into highly ordered body-centered tetragonal lattices of up to a few micrometers. Although measurements on disordered ensembles have been carried out, determining the magnetic properties of individual mesoscopic crystals is challenging due to their small total magnetic moment. Here, we overcome these challenges by utilizing sensitive dynamic cantilever magnetometry to study individual micrometer-sized $γ\text{-Fe}_2\text{O}_3$ mesocrystals. These measurements reveal an unambiguous cubic anisotropy, resulting from the crystalline anisotropy of the constituent maghemite nanoparticles and their alignment within the mesoscopic lattice. The signatures of anisotropy and its orgins come to light because we combine the self-assembly of highly ordered mesocrystals with the ability to resolve their individual magnetism. This combination is promising for future studies of the magnetic anisotropy of other nanoparticles, which are too small to investigate individually.
