Summers B, Chen Y, Dahal A, Singh D K
Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
Sci Rep. 2017 Nov 22;7(1):16080. doi: 10.1038/s41598-017-15786-8.
Artificial magnetic honeycomb lattice provides a two-dimensional archetypal system to explore novel phenomena of geometrically frustrated magnets. According to theoretical reports, an artificial magnetic honeycomb lattice is expected to exhibit several phase transitions to unique magnetic states as a function of reducing temperature. Experimental investigations of permalloy artificial honeycomb lattice of connected ultra-small elements, [Formula: see text] 12 nm, reveal a more complicated behavior. First, upon cooling the sample to intermediate temperature, [Formula: see text] 175 K, the system manifests a non-unique state where the long range order co-exists with short-range magnetic charge order and weak spin ice state. Second, at much lower temperature, [Formula: see text] 6 K, the long-range spin solid state exhibits a re-entrant behavior. Both observations are in direct contrast to the present understanding of this system. New theoretical approaches are needed to develop a comprehensive formulation of this two dimensional magnet.
人工磁蜂窝晶格提供了一个二维原型系统，用于探索几何受挫磁体的新现象。根据理论报告，随着温度降低，人工磁蜂窝晶格预计会表现出几种向独特磁态的相变。对连接的超小元素（尺寸为12纳米）的坡莫合金人工蜂窝晶格的实验研究揭示了一种更为复杂的行为。首先，将样品冷却至中间温度（175K）时，系统呈现出一种非唯一状态，其中长程有序与短程磁荷有序以及弱自旋冰态共存。其次，在更低温度（6K）下，长程自旋固态表现出重入行为。这两个观察结果与目前对该系统的理解直接相反。需要新的理论方法来全面阐述这种二维磁体。
