Reduction of Transition Layer Thickness Showing Incoherent Switching Behavior in Single CoCrPt–SiO$_{2}$ Perpendicular Media

Magnetic switching behavior and activation volume (V
_act
) for CoCrPt-SiO
₂
single layer media on two intermediate layer (IL) types of conventional Ru
₁
/Ru
₂
(IL1) and RuCr/Ru
₂
(IL2) are investigated. Ru
₁
and Ru
₂
indicate the Ru layer deposited at low and high pressure of Ar, respectively. Replacement of Ru
₁
with RuCr improves both crystallographic c-axis orientation (Deltathetas
₅₀
) of <2.5deg and its crystallinity. This improvement helps achieve higher coercivity at thinner magnetic layer thickness (t
_mag
). Both IL exhibit a similar trend in angular dependence of remanent coercivity (H
_cr
) but minimum value of H
<sub>cr

45deg</sub>
/H
<sub>cr

0deg</sub>
is observed at t
_mag
= 15 nm for IL1 and 9 nm for IL2. The use of IL2 significantly reduces incoherent switching behavior at thinner t
_mag
. Values of V
_act
for both IL decrease with increasing t
_mag
but IL2 provides considerably higher V
_act
than IL1. In the media with IL2, higher H
_c
and more coherent switching behavior at thinner t
_mag
can be understood by contributions of narrower Deltathetas
₅₀
, thinner transition layer thickness showing incoherent switching behavior, and higher V
_act
.