Modelling of hysteresis and dynamics in nanostructured magnetic elements.

We are working in micromagnetic modelling of hysteresis and dynamics in nanostructured magnetic elements such as  magnetic stripes, dots, antidots and nanowires. Our goal is understanding of magnetisation processes in relation to the shape, geometry and interaction between magnetic elements. In this topic we are closely working with experimental groups with the aim to explain magnetic measurements.  Our recent results include:

  • Understanding of coercivity mechanisms in system of  lythographically prepared antidots [1] and antidots from alumina templates
  • Modelling of coercivity in magnetic nanostripes [2]
  • Modelling of microwave-assisted switching in micron-sized Py ellipsoids [3].
  • Modelling of MFM images of vortices in Ni triangles [4].  Demonstration of the possibility to control both chirality and polarity  [5].
  • Fast [6]  and slow vortex [7] dynamics in Py circular dots.
  • Micromagnetic modelling of magnetization process in  nanowires [8], nanopilars and antidots and their arrays prepared from alumina templates.

References
[1] F. Garcia-Sanchez, E. Paz, F. Pigazo, O. Chubykalo-Fesenko, F.J. Palomares, J.M. González, F. Cebollada, J. Bartolomé and L.M. Garcia  “Coercivity mechanisms in lithographed antidot arrays.”, Europhys. Lett. 84 (2008) 67002.

[2] F.García-Sánchez and O.Chubykalo-Fesenko “Thermal coercivity mechanism in Fe nanoribbons and stripes”, Appl. Phys. Lett. 93 (2008) 1.

[3]  R. Yanes, R. Rozada, F. Garcia-Sánchez, O. Chubykalo-Fesenko, P. Martin Pimentel, B. Leven and B. Hillebrands “Modeling of microwave-assisted switching in micron-sized magnetic ellipsoids” , Phys. Rev.B 79 (2009) 22427.

[4] M.Jaafar, R.Yanes, A.Asenjo, O.Chubykalo-Fesenko, M.Vazquez, E.M.Gonzalez and J.L.Vicent “Field induced vortex dynamics in magnetic Ni  nanotriangles”, Nanotechnology 19 (2008) 285717.

[5] M.Jaafar, R.Yanes, D.Perez de Lara, O.Chubykalo-Fesenko, A.Asenjo, E.M.Gonzalez, J.Anguita, M.Vázquez and J.L.Vicent “Control of the chirality and polarity of magnetic vortices in  triangular dots” , Phys.Rev.B 81 (2010) 054439.

[6] K.Guslienko, R.Hernandez Heredero and O.Chubykalo-Fesenko  “Nonlinear gyrotropic vortex dynamics in ferromagnetic dots”, Phys.Rev.B 82 (2010) 014402.

[7]  G.Kakazei, M.Ilyin, O.Chubykalo-Fesenko, J.Gonzalez, A.Serga, A.Chumak, P.A.Beck, B.Laegel, B.Hillebrands, K.Y.Guslienko «Slow magnetisation dynamics and energy barrier near vortex state nucleation in circular permalloy dots», Appl. Phys. Lett.  99 (2011) 052512.

[8] L.G.Vivas, R.Yanes, O.Chubykalo-Fesenko, M.Vazquez «Coercivity of ordered arrays of magnetic nanowires with controlled variable lengths», Appl. Phys. Lett. 98 (2011) 232507.

Recent simulations

(a) Hysteresis process in Fe antidots; (b) Microwave-assisted demagnetisation in micron-sized Py ellipsoid; (c) Vortices in Ni triangular dots; (d) Magnetisation reversal in an array of Co nanowires.