Effect of Oblique Versus Normal Deposition on the Properties of Perpendicularly Magnetized L10 FePd Thin Films

Materials such as L1
₀
Fe-based alloys with perpendicular magnetic anisotropy derived from crystal structure have the potential to deliver higher thermal stability of magnetic memory elements compared to materials whose anisotropy is derived from surfaces and interfaces. A number of processing parameters enable control of the quality and texture of L1
₀
FePd; among them are substrate, deposition temperature, pressure, and seed and buffer layer. The angle of inclination between the substrate and the sputtering target can also impact the texture of L1
₀
crystallization of sputtered FePd and magnetic properties of the derived thin films. This letter examines the difference between FePd layers that have been magnetron sputter deposited on Cr(15 nm)/Pt, Ir, or Ru(4 nm)/FePd (8 nm)/Ru(2 nm)/Ta(3 nm) substrate layers at an oblique angle (30° tilt from the sputtering target) versus normal incidence (target facing the substrate). X-ray diffraction, ferromagnetic resonance spectroscopy, and vibrating sample magnetometry were used to compare the degree of L1
₀
order and static and dynamic properties of films deposited under both conditions. The films grown using the oblique orientation exhibit stronger degree of L1
₀
orientation, larger magnetic anisotropy energy, and lower Gilbert damping, on all three buffer layers.