Electrochemical deposition of thin magnetic layers

Magnetic layers and layered structures with defined physical properties are of high interest for magnetoelectronic and magnetoelectromechanical applications as well as for magnetic data storage. New deposition technologies become more important in industrial branches for magnetic applications. Electrochemical deposition methods are favoured due to their low costs compared to physical deposition methods. Due to the increasing miniaturisation of microelectronic components the thickness of such layers is only some nm. This is a challenge for electrochemical processes and requires new approaches. Here the superimposition of magnetic fields during the electrochemical deposition process is used to optimize film growth. Dependent on the orientation, strength and homogeneity of the magnetic field the deposition process of Co is influenced and therefore, the structure and morphology of the layers can be changed specifically. In recent years, the FePt alloy has attracted growing interest as a hard magnetic material competing with the well established NdFeB. This is due to the excellent hard magnetic properties of the ordered FePt L10 phase. It exhibits a saturation magnetization of 1.4 T and a very high magnetocrystalline anisotropy of 107 J/m3. With a proceeding miniaturization of devices, materials costs become less important compared to processing costs and therefore, FePt films are expected to compete with rare earth based hard magnetic films. Potential applications of FePt films are as media in high density magnetic storage and as micromagnets in microelectromechanical systems (MEMS). Up to now, most FePt films are produced using physical vapour deposition techniques like Sputtering, Pulsed Laser Deposition or Electron Beam Evaporation. In contrast to those techniques, the electrodeposition of FePt promises a less expensive and simple way to deposit FePt films, as no vacuum environment is required and less material is wasted.