Cīmurs J, Cēbers A
University of Latvia, Zeļļu-8, Rīga, LV-1002, Latvia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Dec;88(6):062315. doi: 10.1103/PhysRevE.88.062315. Epub 2013 Dec 27.
A model of a single ferromagnetic particle with a finite coupling energy of the magnetic moment with the body of the particle is formulated, and regimes of its motion in a rotating magnetic field are investigated. Regimes are possible that are synchronous and asynchronous with the field. In a synchronous regime the easy axis of the particle is in the plane of the rotating magnetic field at low frequencies (a planar regime) and on the cone at high frequencies (a precession regime). The stability of these regimes is investigated, and it is shown that the precession regime is stable for field strengths below the critical value. In a particular range of field strength value, irreversible jumps of the magnetic moment take place in the asynchronous planar regime. The stability of this regime is investigated, and it is shown that it is stable for field strengths above the critical value, which depends on the frequency. The implications of these results for the energy dissipation in a rotating field are analyzed, and it is shown that the maximum of the heat production near the transition to the synchronous regime is flattened out by the transition to the precession regime.
建立了一个单铁磁粒子模型，该粒子磁矩与粒子本体具有有限的耦合能，并研究了其在旋转磁场中的运动状态。存在与磁场同步和异步的状态。在同步状态下，粒子的易轴在低频时位于旋转磁场平面内（平面状态），在高频时位于圆锥面上（进动状态）。研究了这些状态的稳定性，结果表明，对于低于临界值的场强，进动状态是稳定的。在特定的场强值范围内，异步平面状态下会发生磁矩的不可逆跳跃。研究了该状态的稳定性，结果表明，对于高于临界值（取决于频率）的场强，它是稳定的。分析了这些结果对旋转磁场中能量耗散的影响，结果表明，在向同步状态转变附近的热产生最大值通过向进动状态的转变而变得平缓。
