Influence of multilayer modulation on structural and magnetic features in the Pt/Sm-Co system

In this work, we study the influence of Pt underlayer in Pt/Sm-Co/Pt trilayers and in Pt/Sm-Co multilayers. In both cases, Pt underlayer seems to impose better crystallinity to Sm-Co layer and certainly promotes the evolution of the hard-magnetic SmCo5 phase. Particularly, in the case of multilayer form, where multiple interlayers of Pt each one serving as a dedicated underlayer for the deposition of a specific Sm-Co layer, enhanced crystallinity is observed. Moreover, post-deposition annealing facilitates these features at relatively lower temperatures (∼400 °C) than those met in thin-film cases. This behavior is also followed by enhancement of saturation magnetization, while higher temperature post-deposition thermal treatment seems to deteriorate structural and magnetic features. If annealing temperature gets over 550 °C macroscopic magnetic features depress, probably due to domination of annealing-activated processes such as Sm oxidation and formation of non-magnetic phases since Pt diffuses throughout the whole magnetic layer.