Stacking Faults and Their Effect on Magnetocrystalline Anisotropy in Co and Co-Alloy Thin Films

Stacking faults in (1010) unicrystal Co and Co-alloy thin films have been analyzed by the electron diffraction technique. As predicted no diffraction contrast of stacking faults could be observed when the beam is parallel to the [1010] direction. However, both by plan-view TEM observation and electron diffraction along the [1120] direction reveal that the stacking fault density in biased pure Co (1010) thin films is much lower than that in unbiased ones. The addition of Cr in Co films significantly reduces stacking fault density whereas the addition of 8at% Pt leads to a considerable increase in stacking fault density. Our results show that stacking faults in Co thin films significantly, and negatively, affect the anisotropy energy density and its temperature dependence.