Low Gilbert damping and high thermal stability of Ru-seeded L1-phase FePd perpendicular magnetic thin films at elevated temperatures.

Bulk perpendicular magnetic anisotropy materials are proposed to be a promising candidate for next-generation ultrahigh density and ultralow energy-consumption spintronic devices. In this work, we experimentally investigate the structure, thermal stability, and magnetic properties of FePd thin films seeded by a Ru layer. An -phase Ru layer induces the highly-ordered L1-phase FePd thin films with perpendicular magnetic anisotropy ( ~ 10.1 Merg/cm). The thermal stability of FePd samples is then studied through the annealing process. It is found that a ~ 6.8 Merg/cm can be obtained with the annealing temperature of 500 °C. In addition, the damping constant , an important parameter for switching current density, is determined as a function of the testing temperature. We observe that increases from 0.006 to 0.009 for as-deposited FePd sample and from 0.006 to 0.012 for 400 °C-annealed FePd sample as the testing temperature changes from 25 °C to 150 °C. These results suggest that Ru-seeded FePd provides great potential in scaling perpendicular magnetic tunnel junctions below 10 nm for applications in ultralow energy-consumption spintronic devices.