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-SiO₂ single layer media on two intermediate layer (IL) types of conventional Ru₁/Ru₂ (IL1) and RuCr/Ru₂ (IL2) are investigated. Ru₁ and Ru₂ indicate the Ru layer deposited at low and high pressure of Ar, respectively. Replacement of Ru₁ with RuCr improves both crystallographic c-axis orientation (Deltathetas₅₀) 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_{cr 45deg}/H_{cr 0deg} 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 Deltathetas₅₀, thinner transition layer thickness showing incoherent switching behavior, and higher V_act.