We describe methods to measure ferromagnetic resonance in both unpatterned blanket films and patterned nanostructures, with the goal of determining both the anisotropy and the damping of ferromagnetic materials intended for spin-torque memory applications. Measurement of blanket films relies on vector network analyzer measurements with a coplanar waveguide loaded with the material to be measured. A novel magneto-optic method is used to measure the dynamics in individual nanomagnets. In both cases, the theory for the measurement technique is presented, with the aim of guiding the user in optimizing the signal-to-noise ratio of the measurement.

We have measured the spin torques of beta-Tantalum / Co20Fe60B20 bilayers versus Ta thickness at room temperature using an FMR technique. The spin Hall coefficient was calculated both from the observed change in damping coefficient of the ferromagnet with Ta thickness, and from the ratio of the symmetric and anti-symmetric components of the FMR signal. Results from these two methods yielded values for the spin Hall coefficient of -0.090+/-0.005 and -0.11+/-0.01, respectively. We have also identified a significant out-of-plane spin torque originating from Ta, which is constant with Ta thickness. We ascribe this to an interface spin orbit coupling, or Rashba effect, due to the strength and constancy of the torque with Ta thickness. From fitting measured data to a model including interface spin orbit coupling, we have determined the spin diffusion length for beta-Tantalum to be ~2.5 nm.

We demonstrate the synthesis of large-area graphene on Co, a complementary metal-oxide-semiconductor (CMOS)-compatible metal, using acetylene (C(2)H(2)) as a precursor in a chemical vapor deposition (CVD)-based method. Cobalt films were deposited on SiO(2)/Si, and the influence of Co film thickness on monolayer graphene growth was studied, based on the solubility of C in Co. The surface area coverage of monolayer graphene was observed to increase with decreasing Co film thickness. A thorough Raman spectroscopic analysis reveals that graphene films, grown on an optimized Co film thickness, are principally composed of monolayer graphene. Transport properties of monolayer graphene films were investigated by fabrication of back-gated graphene field-effect transistors (GFETs), which exhibited high hole and electron mobility of ∼1600 cm(2)/V s and ∼1000 cm(2)/V s, respectively, and a low trap density of ∼1.2 × 10(11) cm(-2).