Electromagnetic Breathers and Periodic Loops in a Ferromagnet with the Uniaxial Anisotropy
The nonlinear magnetization dynamics of an uniaxial anisotropy ferromagnet thin film under an external magnetic field is analytically studied. The celebrated Landau–Lifshitz equation depicts the magnetization dynamics of the anisotropy ferromagnetic thin film and the Maxwell’s equations govern the propagation dynamics of electromagnetic wave along the magnetic anisotropy axis. By means of a reductive perturbation approach, the dynamics equations of the system can be reduced as a modified Korteweg-de Vries equation, which exist a exact breather solution. We find that the excitations of magnetization of the ferromagnetic thin film and the magnetic induction and magnetic field of the electromagnetic wave can be governed by the breather mode. Our results show that the easy axis-component of the magnetization is a highly localized magnetized state in the form of the breather and the other-components of the magnetization are evolving like localized periodic loops when the breather mode is excited, which is very interesting. Up to now, few similar results have been reported.
KeywordsBreathers Periodic loops Ferromagnet The uniaxial anisotropy
This work was supported by the National Natural Science Foundation of China under Grant No. 11604121, by the Scientific Research Fund of Hunan Provincial Education Department under Grant No. 16B210 and 16A170, and by the Natural Science Fund Project of Hunan Province under Grant No. 2017JJ3255.
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