Ribeiro I R B, Nascimento F S, Ferreira S O, Moura-Melo W A, Costa C A R, Borme J, Freitas P P, Wysin G M, de Araujo C I L, Pereira A R
Laboratory of Spintronics and Nanomagnetism (LabSpiN), Departamento de Física, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil.
Instituto Federal do Espírito Santo, Alegre, 36570-900, Espírito, Santo, 29520-000, Brazil.
Sci Rep. 2017 Oct 25;7(1):13982. doi: 10.1038/s41598-017-14421-w.
In this work, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by a and b respectively). Arrays with three different aspect ratios γ = a/b = [Formula: see text], [Formula: see text] and [Formula: see text] are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough γ. Our results also insinuate that the string tension connecting two magnetic monopoles in a pair vanishes in rectangular lattices with a critical ratio γ = γ = [Formula: see text], supporting previous theoretical predictions.
在这项工作中，我们构建并通过实验研究了形成具有不同晶格参数的二维人工自旋冰的偶极子受挫阵列（矩形阵列，水平和垂直晶格间距分别用a和b表示）。研究了具有三种不同纵横比γ = a/b = [公式：见正文]、[公式：见正文] 和 [公式：见正文] 的阵列。还给出了这些相同参数的低能退磁构型的理论计算。退磁样品的实验数据证实了大部分理论结果。然而，最高能量拓扑结构（双电荷单极子）在我们的理论模型中并未出现，而在足够大的γ的实验中可以看到它们。我们的结果还暗示，在临界比γ = γ = [公式：见正文] 的矩形晶格中，连接一对磁单极子的弦张力消失，这支持了先前的理论预测。
