Magnetic Properties and Magnetization Dynamics of Magnetic Tunnel Junction Bottom Electrode With Different Buffer Layers

We present the research on magnetic tunnel junction bottom electrodes CoFeB prepared on different buffer layers: 5Ta/30CuN/5Ta, 5Ta/15CuN/3Ta/15CuN/5Ta, 5Ta/10CuN/5Ta, 5Ta, 10Ta, and 5Ta/10Ru/5Ta (all thicknesses in nanometers). The buffer crystallographic microstructures were characterized with X-ray diffraction measurements while the roughness was investigated with atomic force microscopy measurements. We show the influence of crystallographic texture and surface roughness on the coercivity and anisotropy fields. Ferromagnetic resonance measurements were performed with a scalar network analyzer to determine the spin-wave dispersion relation of the precession frequency and the damping parameter. The results were confirmed with pulse inductive microwave magnetometry measurements.