Exploring the phase diagram of 3D artificial spin-ice
Exploring the phase diagram of 3D artificial spin-ice
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DOI：
10.1038/s42005-023-01338-2
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发表时间：
2022-11
影响因子：
5.5
通讯作者：
M. Saccone;Arjen van den Berg;Edward Harding;Shobhna Singh;S. Giblin;F. Flicker;S. Ladak
中科院分区：
文献类型：
--
作者：
M. Saccone;Arjen van den Berg;Edward Harding;Shobhna Singh;S. Giblin;F. Flicker;S. Ladak
人工自旋冰由组织成受挫晶格的单域磁性纳米线的光刻阵列组成。这些几何形状通常是二维的，允许直接探索与挫折、拓扑和涌现相关的物理学。最近，三维几何已经实现，其中浮现的单极子的输运可以直接在表面上可视化。在这里，我们对三维人工自旋-冰相图进行了探索，在该相图中，偶极子被放置在钻石键晶格几何中。我们发现了一个丰富的相图，它由双电荷单极晶体、单电荷单极晶体和与库仑相关联的具有夹点的传统自旋冰组成。在实验退磁系统中，对称性的破坏迫使表面形成铁磁条纹，从而阻止了较低能量的双电荷单极晶体的形成。相反，我们观察到的是叠加在冰层背景上的单磁荷微晶。微晶的形成是由于3D顶点周围磁荷的分布，这在局部有利于单极的形成。
Artificial spin-ices consist of lithographic arrays of single-domain magnetic nanowires organised into frustrated lattices. These geometries are usually two-dimensional, allowing a direct exploration of physics associated with frustration, topology and emergence. Recently, three-dimensional geometries have been realised, in which transport of emergent monopoles can be directly visualised upon the surface. Here we carry out an exploration of the three-dimensional artificial spin-ice phase diagram, whereby dipoles are placed within a diamond-bond lattice geometry. We find a rich phase diagram, consisting of a double-charged monopole crystal, a single-charged monopole crystal and conventional spin-ice with pinch points associated with a Coulomb phase. In experimental demagnetised systems, broken symmetry forces formation of ferromagnetic stripes upon the surface, forbidding the lower energy double-charged monopole crystal. Instead, we observe crystallites of single magnetic charge, superimposed upon an ice background. The crystallites are found to form due to the distribution of magnetic charge around the 3D vertex, which locally favours monopole formation.