Effect of Pt and FePt Layer Thickness on Microstructure and Magnetic Properties of L10 FePt Films With Perpendicular Anisotropy

The effect of the thicknesses of the Pt intermediate layer and FePt magnetic layer in CrV/Pt/FePt multilayers on the microstructure and magnetic properties for the perpendicular magnetic anisotropy was investigated. The Pt (0-4 nm) and FePt (7-28 nm) layers were deposited on a 90 nm-thick Cr
₉₄
V
₆
underlayer at 350 °C, and the crystal structure and magnetic properties of the fabricated CrV/Pt/FePt multilayers were characterized. X-ray diffraction and vibrating sample magnetometer measurements revealed that the out-of-plane coercivity (H
_c-out
) and squareness increase when the Pt intermediate layer is deposited between CrV and FePt because it protects against diffusion of Cr and V atoms into the FePt magnetic layer during deposition. In addition, we confirmed that H
_c-out
and squareness decrease with increasing FePt layer thickness in the range of 7-28 nm. As a result, the maximum H
_c-out
, S, and squareness were obtained for a multilayer with a CrV thickness of 90 nm, Pt thickness of 2 nm, and FePt thickness of 7 nm. This paper shows that highly ordered FePt L1
₀
(001) can be fabricated by sublayer thickness control.