Enhanced unidirectional anisotropy of the Co90Fe10/CrMnPt system by the NiO capping layer

The effect of a capping layer on the exchange coupled Co90Fe10/CrMnPt system was investigated. The NiO capping layer is able to enhance the unidirectional anisotropy Ke of the Co90Fe10/CrMnPt system to ∼0.302–0.345 erg/cm2. This strong Ke is thought to be caused by large stress emancipation of the NiO film through thermal annealing, which assists spreading of the CrMnPt lattice distortion in a desirable direction. This lattice distortion, in turn, leads to the enhancement of the CrMnPt magnetocrystalline anisotropy. The NiO capped Co90Fe10/CrMnPt system exhibits the same high blocking temperature TB of ∼300 °C as the noncapped one, i.e., there is no TB reduction due to the amplification of the CrMnPt lattice distortion.