Intermediate magnetization state and competing orders in Dy2Ti2O7 and Ho2Ti2O7.
Intermediate magnetization state and competing orders in Dy2Ti2O7 and Ho2Ti2O7.
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DOI：
10.1038/ncomms12592
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发表时间：
2016-08-25
影响因子：
16.6
通讯作者：
Grigera, S. A.
中科院分区：
文献类型：
--
作者：
Borzi, R. A.;Gomez Albarracin, F. A.;Rosales, H. D.;Rossini, G. L.;Steppke, A.;Prabhakaran, D.;Mackenzie, A. P.;Cabra, D. C.;Grigera, S. A.
在受挫的磁性材料中，自旋冰作为一个特别有趣的系统脱颖而出。三维中的残余熵、冻结和玻璃化、Kasteleyn跃迁和激发的分馏化都源于一个简单的经典哈密顿量。但是，通常的自旋-冰哈密顿量是对实验系统的正确描述吗？在这里，我们通过使用矢量磁铁测量两种研究最多的自旋-冰化合物Dy2Ti2O7和Ho2Ti2O7的磁化率来解决这个问题。利用这些结果，在焦绿石晶格可能扭曲的理论分析的指导下，我们构造了一个有效的哈密顿量，并用蒙特卡罗模拟对其进行了探索。我们展示了该哈密顿量如何重现实验结果，包括中间极化相的形成，并给出了关于真实自旋-冰系统可能的基态的重要信息。我们的工作表明了一种不同寻常的情况，在这种情况下，扭曲可能有助于保留而不是缓解挫折的影响。经典的哈密顿量捕捉到了自旋冰材料的关键性质，如剩余熵和分数激发。在这里，作者给出了激发具有晶格扭曲的哈密顿量的极化相变的实验结果，该哈密顿量预测了中间磁化态和竞争基态顺序。
Among the frustrated magnetic materials, spin-ice stands out as a particularly interesting system. Residual entropy, freezing and glassiness, Kasteleyn transitions and fractionalization of excitations in three dimensions all stem from a simple classical Hamiltonian. But is the usual spin-ice Hamiltonian a correct description of the experimental systems? Here we address this issue by measuring magnetic susceptibility in the two most studied spin-ice compounds, Dy2Ti2O7 and Ho2Ti2O7, using a vector magnet. Using these results, and guided by a theoretical analysis of possible distortions to the pyrochlore lattice, we construct an effective Hamiltonian and explore it using Monte Carlo simulations. We show how this Hamiltonian reproduces the experimental results, including the formation of a phase of intermediate polarization, and gives important information about the possible ground state of real spin-ice systems. Our work suggests an unusual situation in which distortions might contribute to the preservation rather than relief of the effects of frustration. A classical Hamiltonian captures key properties of spin ice materials such as residual entropy and fractionalized excitations. Here, the authors present experimental results of the polarization transition that motivate a Hamiltonian with lattice distortions, which predicts an intermediate magnetization state and competing ground state orders.
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影响因子：
64.8
作者：
Ramirez, AP;Hayashi, A;Shastry, BS
通讯作者：
Shastry, BS
影响因子：
8.6
作者：
Bramwell, ST;Harris, MJ;Fennell, T
通讯作者：
Fennell, T
影响因子：
8.6
作者：
Ruff, JPC;Melko, RG;Gingras, MJP
通讯作者：
Gingras, MJP
影响因子：
3.7
作者：
Gomez Albarracin, F. A.;Cabra, D. C.;Rossini, G. L.
通讯作者：
Rossini, G. L.
影响因子：
0.9
作者：
Grigera, S. A.;Borzi, R. A.;Grigera, T. S.
通讯作者：
Grigera, T. S.