Perpendicular Magnetic Anisotropy Materials for Spintronics Applications

Abstract

Ferromagnetic materials with large perpendicular magnetic anisotropy (PMA) are investigated for spin transfer torque magnetic random access memory (STT-MRAM) elements, as they fulfill thermal stability at low dimensions and lower the critical current density for STT switching. L10-FePt is a potential candidate for such perpendicular systems due to its high magnetocrystalline anisotropy. This thesis revolves around the study of high PMA L10-FePt in pseudo spin valves (PSVs). Different spacer materials, Ag and TiN, were used. The PSV with Ag spacer displayed an improved giant magnetoresistance of 1.1 % compared to the Au, Pt and Pd spacer reported earlier. The use of TiN spacer mitigated the interlayer diffusion issue as TiN was chemically stable towards FePt and was also a good diffusion barrier. The thesis also further demonstrated PSVs consisting of ultra-thin L10-FePt free layer of thickness less than 4 nm, which was desirable for reducing the STT critical current density.