Institut für Computerphysik, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
J Chem Phys. 2013 Dec 7;139(21):214901. doi: 10.1063/1.4832239.
We investigate the structure of a recently proposed magnetic fluid consisting of shifted dipolar (SD) particles in an externally applied magnetic field via computer simulations. For standard dipolar fluids the applied magnetic field usually enhances the dipole-dipole correlations and facilitates chain formation whereas in the present system the effect of an external field can result in a break-up of clusters. We thoroughly investigate the origin of this phenomenon through analyzing first the ground states of the SD-particle systems as a function of an applied field. In a second step we quantify the microstructure of these systems as functions of the shift parameter, the effective interaction parameter, and the applied magnetic field strength. We conclude the paper by showing that with the proper choice of parameters, it is possible to create a system of SD-particles with highly interacting magnetic particles, whose initial susceptibility is below the Langevin susceptibility, and which remains spatially isotropic even in a very strong external magnetic field.
我们通过计算机模拟研究了由在外磁场中移动的偶极子（SD）粒子组成的新型磁流体的结构。对于标准偶极子流体，外加磁场通常会增强偶极子-偶极子相关性并促进链形成，而在本系统中，外场的作用可能导致簇的破裂。我们通过分析施加场下 SD 粒子系统的基态，彻底研究了这种现象的起源。在第二步中，我们将这些系统的微观结构作为位移参数、有效相互作用参数和外加磁场强度的函数进行量化。我们通过展示以下内容结束本文：通过选择适当的参数，可以创建一个具有高相互作用磁性粒子的 SD 粒子系统，其初始磁化率低于朗之万磁化率，并且即使在外加磁场非常强的情况下，仍然保持各向同性。
