Two-dimensional ferromagnetism of a 3He film: influence of weak frustration.
Two-dimensional ferromagnetism of a 3He film: influence of weak frustration.
复制标题
3He 薄膜的二维铁磁性：弱挫败的影响。
DOI：
10.1103/physrevlett.111.125302
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发表时间：
2013
影响因子：
8.6
通讯作者：
Casey A
中科院分区：
文献类型：
--
作者：
Casey A
吸附在石墨原子平面上的薄膜为研究三角形晶格上的二维磁性提供了一个模型系统。我们研究了第二层的基态为全极化铁磁体的区域。利用宽带SQUID探测，在自旋-翻转转变上方的低场范围内，在0.3-200nMK的宽温度范围内，使我们能够解开样品有限尺寸效应和磁场对自旋波谱的影响。我们证明了自旋波谱是由不同于决定高温磁性的有效交换常数决定的。这可以用受挫的原子环交换来理解。
films adsorbed on the atomically flat surface of graphite provide a model system for the study of two-dimensional magnetism on a triangular lattice. We have made a study of the regime in which theground state of the secondlayer is a fully polarized ferromagnet. NMR, using broadband SQUID detection, at a range of low fields above the spin-flop transition, and over a wide temperature range 0.3–200 mK, has enabled us to disentangle the influence of sample finite size effects and magnetic field on the spin-wave spectrum. We demonstrate that the spin-wave spectrum is governed by a different effective exchange constant than that determining the high temperature magnetism. This is understood in terms of frustrated atomic ring exchange.