Controlled magnetization reversal and magnetic spectra of artificial Sierpinski-fractal structure

摘要

We show by micromagnetic simulations that the magnetization reversal and magnetic spectra can be effectively controlled by patterning a ferromagnet into novel Sierpinski-fractal structure. As the number of iterations increases from 1 to 6, the knees in the hysteresis loop rise from 1 to 27 and the way of magnetization reversal changes. Moreover, the influence of Sierpinski-fractal structure on magnetic spectra increases as the iteration number increases, especially for the fifth- and sixth-iteration films, all the resonant peaks in the magnetic spectra are caused by the fractal structure. A blueshift of the resonance peaks occurs as the number of iterations increases, which is due to the increasing number of corners associated with fractal structures. Temperature has little influence on the hysteresis loop and the magnetization reversal mode for the third-iteration sample, while results in the decrease of the coercivity for the sixth-iteration one. addition, the remanence states of the Sierpinski-fractal structures have a character of self-similarity, typical for fractal structures.