Magnetic switching behavior and activation volume (Vact) 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 (tmag). Both IL exhibit a similar trend in angular dependence of remanent coercivity (Hcr) but minimum value of Hcr 45deg/Hcr 0deg is observed at tmag= 15 nm for IL1 and 9 nm for IL2. The use of IL2 significantly reduces incoherent switching behavior at thinner tmag. Values of Vact for both IL decrease with increasing tmag but IL2 provides considerably higher Vact than IL1. In the media with IL2, higher Hc and more coherent switching behavior at thinner tmag can be understood by contributions of narrower Deltathetas50, thinner transition layer thickness showing incoherent switching behavior, and higher Vact.