Micromagnetic simulation of exchange coupled ferri-/ferromagnetic   composite in bit patterned media
  Ferri-/ferromagnetic exchange coupled composites are promising candidates for bit patterned media because of the ability to control the magnetic properties of the ferrimagnet by its composition. A micromagnetic model for the bilayer system is presented where we also incorporate the microstructural features of both layers. Micromagnetic finite element simulations are performed to investigate the magnetization reversal behaviour of such media. By adding the exchange coupled ferrimagnet to the ferromagnet, the switching field could be reduced by up to $40\,\%$ and also the switching field distribution is narrowed. To reach these significant improvements, an interface exchange coupling strength of $2\,\mathrm{mJ/m^2}$ is required. 
Harald Oezelt, Alexander Kovacs, Phillip Wohlh\"uter, Eugenie Kirk,   Dennis Nissen, Patrick Matthes, Laura Jane Heyderman, ...
physics.comp-ph cond-mat.mtrl-sci