Effects of seedlayers on magnetic properties and microstructure in CoCr(Ta)/Cr thin films

In order to improve the magnetic properties of Co-based thin films, different seedlayers (SiO, ITO, SiO 2 , Ag and Al) have been applied on a PET substrate. The thickness of Cr underlayers and of magnetic layers is varied to obtain thin films with optimal magnetic properties. The magnetic properties of CoCrTa and CoCrPt thin films are improved clearly when the magnetic layer is thin. Specifically, the coercive force of CoCrPt thin films reaches 100 kA/m sputtered with a sputter pressure 50 mTorr on pure argon at room temperature. AFM topographies indicate that the average grain size and the grain shape of thin films vary with thickness of Cr underlayer and of magnetic layer. This influences the magnetic interactions inside thin films and subsequently adjusts the magnetic properties. The crystal structure of each thin film with a seedlayer is improved as well.