Self-organization in dipolar cube fluids constrained by competing anisotropies
Self-organization in dipolar cube fluids constrained by competing anisotropies
复制标题
受竞争各向异性约束的偶极立方流体中的自组织
DOI：
10.1039/c7sm02174g
复制
发表时间：
2018
期刊：
影响因子：
3.4
通讯作者：
Sacanna, Stefano
中科院分区：
文献类型：
--
作者：
Rossi, Laura;Donaldson, Joe G.;Meijer, Janne-Mieke;Petukhov, Andrei V.;Kleckner, Dustin;Kantorovich, Sofia S.;Irvine, William T.;Philipse, Albert P.;Sacanna, Stefano
对于磁铁矿球形纳米颗粒，晶体中的偶极矩的取向不影响零场或场诱导结构的形态。然而，对于非球形颗粒，颗粒形状和磁矩方向之间的相互作用可引起不寻常的行为，特别是当磁矩不沿着颗粒对称轴对齐时。本文首次揭示了赤铁矿立方颗粒独特的磁性，并给出了立方颗粒偶极矩的精确取向。使用实验和计算机模拟相结合，我们表明，偶极赤铁矿立方体自组织成偶极链的形态显着不同的领域，并证明这些结构的出现是由竞争的各向异性相互作用所造成的颗粒的形状各向异性和固定的偶极矩。此外，我们已经分析确定了一个特定的能量之间的相互作用，和熵在微观层面上，并发现一个非正统的熵的贡献介导的组织的粒子到扭结性质的偶极链。
For magnetite spherical nanoparticles, the orientation of the dipole moment in the crystal does not affect the morphology of either zero field or field induced structures. For non-spherical particles however, an interplay between particle shape and direction of the magnetic moment can give rise to unusual behaviors, in particular when the moment is not aligned along a particle symmetry axis. Here we disclose for the first time the unique magnetic properties of hematite cubic particles and show the exact orientation of the cubes' dipole moment. Using a combination of experiments and computer simulations, we show that dipolar hematite cubes self-organize into dipolar chains with morphologies remarkably different from those of spheres, and demonstrate that the emergence of these structures is driven by competing anisotropic interactions caused by the particles' shape anisotropy and their fixed dipole moment. Furthermore, we have analytically identified a specific interplay between energy, and entropy at the microscopic level and found that an unorthodox entropic contribution mediates the organization of particles into the kinked nature of the dipolar chains.