论文标题
磁性纳米颗粒的磁性和摩擦能损失的自洽解决方案
Self-consistent solution of magnetic and friction energy losses of a magnetic nanoparticle
论文作者
论文摘要
我们提出了一个简单的仿真模型，用于分析磁性流体中磁性纳米颗粒的磁性和摩擦损失，受到交替磁场的影响。假设粒径低于单域极限，我们使用宏生方法并求解与机械扭矩方程相连的Landau-Lifshitz-Gilbert方程。尽管它很简单，但提出的模型表现出令人惊讶的富含物理学，并根据粒子和场的初始布置对不同的损耗过程进行了详细的分析。取决于不同稳态的参数区域：一个具有主导的Néel松弛和高磁损耗的区域，而另一个区域则在低场或低频处具有高摩擦力损失。即使在整个方案边界之间，能量也会连续增加，直到频率高于Brownian松弛极限。在较高的频率下，稳态也可以取决于外部场中粒子的初始方向。比较并讨论了一般行为和特殊情况及其特定的吸收率。
We present a simple simulation model for analysing magnetic and frictional losses of magnetic nano-particles in viscous fluids subject to alternating magnetic fields. Assuming a particle size below the single-domain limit, we use a macrospin approach and solve the Landau-Lifshitz-Gilbert equation coupled to the mechanical torque equation. Despite its simplicity the presented model exhibits surprisingly rich physics and enables a detailed analysis of the different loss processes depending on field parameters and initial arrangement of the particle and the field. Depending on those parameters regions of different steady states emerge: a region with dominating Néel relaxation and high magnetic losses and another region region with high frictional losses at low fields or low frequencies. The energy increases continuously even across regime boundaries up to frequencies above the Brownian relaxation limit. At those higher frequencies the steady state can also depend on the initial orientation of the particle in the external field. The general behavior and special cases and their specific absorption rates are compared and discussed.
