Hot electron transport and a quantitative study of ballistic electron magnetic imaging on Co/Cu multilayers

Abstract

We present a study of ballistic hot electron transport in Co/Cu/Co spin valves, using the ballistic electron emission microscope. By comparing samples with various Co thicknesses, we determine the hot electron attenuation length for both the minority- and majority-spin populations in the 1--2 eV energy range. Results are compared to recent calculations in order to qualitatively understand the hot electron attenuation lengths. Using the scanning ability of the microscope, we also present the imaging of different magnetic structures in the Co layers. In particular, we present a detailed study of the variation in $360\ifmmode^\circ\else\textdegree\fi{}$ domain-wall morphology versus applied field. The images are compared with micromagnetic simulations. Good agreement is found that ultimately allows for an estimation of the resolution limits of this microscope.