Hornung J, Gottschall T, Opherden L, Antlauf M, Schwarz M, Kroke E, Herrmannsdörfer T, Wosnitza J
Dresden High Magnetic Field Laboratory (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
Institut für Festkörper- und Materialphysik, TU Dresden, 01062 Dresden, Germany.
J Phys Condens Matter. 2020 Jun 15;32(36). doi: 10.1088/1361-648X/ab9054.
The thermodynamics in spin-ice systems are governed by emergent magnetic monopole excitations and, until now, the creation of a pair of these topological defects was associated with one specific pair-creation energy. Here, we show that the electric dipole moments inherent to the magnetic monopoles lift the degeneracy of their creation process and lead to a splitting of the pair-creation energy. We consider this finding to extend the model of magnetic relaxation in spin-ice systems and show that an electric dipole interaction in the theoretically estimated order of magnitude leads to a splitting which can explain the controversially discussed discrepancies between the measured temperature dependence of the magnetic relaxation times and previous theory. By applying our extended model to experimental data of, various spin-ice systems, we show its universal applicability and determine a dependence of the electric dipole interaction on the system parameters, which is in accordance with the theoretical model of electric dipole formation.
自旋冰系统中的热力学由涌现的磁单极激发所支配，直到现在，一对这些拓扑缺陷的产生都与一个特定的对产生能量相关联。在这里，我们表明磁单极固有的电偶极矩消除了它们产生过程的简并性，并导致对产生能量的分裂。我们认为这一发现扩展了自旋冰系统中磁弛豫的模型，并表明理论估计量级的电偶极相互作用导致的分裂可以解释关于磁弛豫时间的测量温度依赖性与先前理论之间存在争议的差异。通过将我们扩展的模型应用于各种自旋冰系统的实验数据，我们展示了其普遍适用性，并确定了电偶极相互作用对系统参数的依赖性，这与电偶极形成的理论模型一致。
