Anomalous Enhancement of the Magnetic Anisotropy of CoCrPt Alloy Thin Film With Ultrathin Pt Interface

An anomalous enhancement of the coercive field (H
_c
) and of the perpendicular magnetic anisotropy (PMA) of CoCr
₁₀
Pt
₁₀
(at.%) alloy thin films is observed when the magnetic layer is deposited on an ultrathin Pt interlayer (IL). The dc magnetic properties of Pt/CoCr
₁₀
Pt
₁₀
are studied as a function of the magnetic alloy thickness (4-8 nm) and the Pt IL thickness (up to 3 nm). Both the coercive field and the interface anisotropy (Ks) exhibit a non-monotonic dependence on the Pt thickness, showing a characteristic peak value at an intermediate thickness, with a rise in the PMA up to 25%. Similar thickness dependence of H
_c
is observed when using Pd and Ir ILs, but with a more moderate enhancement. This approach provides a means to control and engineer the PMA of CoCrPt alloys, and may find an application in data storage and low-power spinelectronics.