论文标题
自由旋转偶极子的随机致密包装的磁顺序
Magnetic ordering of random dense packings of freely rotating dipoles
论文作者
论文摘要
我们通过数值模拟研究海森堡偶极子的随机致密包装。这些偶极子位于相同球体的中心，这些球体占据了空间中固定的随机位置，并填充了空间体积的分数$φ$。参数$φ$从相当低的值（典型的无定形合奏）到以随机连接的限制出现的最大$φ$ = 0.64。我们假设偶极子可以自由旋转并且没有局部各向异性。除了通常的热力学变量外，此类系统的物理学取决于$φ$。具体而言，我们探索了这些系统的磁性顺序，以描绘温度$φ$平面中的相图。对于$φ\ gtrsim0.49 $，我们发现与强远距离旋转玻璃秩序共存的准长范围铁磁顺序。对于$φ\ Lessim0.49 $，铁磁顺序消失了，让位于旋转镜相，类似于与具有强冷冻疾病的ISINE偶极系统相似的相似。
We study random dense packings of Heisenberg dipoles by numerical simulation. The dipoles are at the centers of identical spheres that occupy fixed random positions in space and fill a fraction $Φ$ of the spatial volume. The parameter $Φ$ ranges from rather low values, typical of amorphous ensembles, to the maximum $Φ$=0.64 that occurs in the random-close-packed limit. We assume that the dipoles can freely rotate and have no local anisotropies. As well as the usual thermodynamical variables, the physics of such systems depends on $Φ$. Concretely, we explore the magnetic ordering of these systems in order to depict the phase diagram in the temperature-$Φ$ plane. For $Φ\gtrsim0.49$ we find quasi-long-range ferromagnetic order coexisting with strong long-range spin-glass order. For $Φ\lesssim0.49$ the ferromagnetic order disappears giving way to a spin-glass phase similar to the ones found for Ising dipolar systems with strong frozen disorder.
