Investigation of magnetic anisotropy and magnetization process of tetragonal distorted FeCo multilayer films

• Perpendicular anisotropy is obtained in [Rh/FeCo(1.5 nm)]n multilayer films.
• With the repeat number(n) increases, effective uniaxial anisotropy(Keff) increases.
• Dynamic magnetization reversal process of multilayers was studied by Kerr microscopy.
• The reversal is governed by the magnetic moments reverse and domain wall movement.
• When n=2–4, the top layer reverses firstly then other layers reverse gradually.

Tetragonal distorted [Rh/FeCo(1.5 nm)]n (n=1–4) multilayer films with strong perpendicular magnetic anisotropy(PMA) were successfully deposited on MgO (100) substrates. Magnetic properties and dynamic magnetization reversal process of the multilayer films have been investigated. With the repeat number of Rh/FeCo bilayer(n) increases from 1 to 4, effective uniaxial anisotropy(Keff) increases from 2.86×106 erg/cm3 to 7.37×106 erg/cm3. For Rh/FeCo(1.5 nm) film, the reversal is governed by the magnetic moments reverse and domain wall movement. For [Rh\FeCo(1.5 nm)]n (n=2–4) films, the top FeCo layer reverses firstly, then other layers reverse gradually. These different reversal behaviors arise from the demagnetization energy and exchange coupling between FeCo layers and multilayer films.