Domain structure and perpendicular magnetic anisotropy in CoFe/Pd multilayers using off-axis electron holography

• Multilayers of Co90Fe10/Pd with different bilayer thickness were deposited using sputtering.
• Sample examined using (S)TEM and off-axis electron holography..
• Co90Fe10 layer thickness was the primary factor determining magnetic domain morphology.
• Perpendicular magnetic isotropy (PMA) decreased as Co90Fe10 layer thickness increased.

Multilayers of Co90Fe10/Pd with different bilayer thicknesses, have been deposited by dc-magnetron sputtering on thermally oxidized Si wafers. Transmission electron microscopy showed that the highly textured crystalline films had columnar structure, while scanning transmission electron microscopy and atomic force microscopy respectively indicated some layer waviness and surface roughness. The magnetic domain structure and perpendicular magnetic anisotropy (PMA) of the Co90Fe10/Pd multilayers were investigated by off-axis electron holography and magnetic force microscopy. The Co90Fe10 layer thickness was the primary factor determining the magnetic domain size and the perpendicular magnetization: both decreased as the thickness increased. The strongest PMA was observed in the sample with the thinnest magnetic layer of 0.45 nm.