Magnetic multilayer (ML) structures comprising a perpendicular magnetic anisotropy (PMA) layer coupled to an in-plane magnetic
anisotropy (IMA) layer are promising materials for zero/low field operating spin-torque oscillators and bit patterned recording media.
The magnetization tilt angle can be easily tuned by varying the IMA layer thickness due to the competition between PMA and
IMA layers. To explore the underlying magnetization reversal mechanism and to further understand the control of tilt angle and
uniformity of the magnetization, the IMA (NiFe, Co, and CoFeB)/PMA (Co/Pd MLs) exchange spring systems are systematically
studied. Experimental data obtained from magnetometry show good agreement with 1-D micromagnetic simulations, allowing us to
design tunable exchange coupled spring as a function of IMA thickness.