Influence of roughness and disorder on tunneling magnetoresistance

Abstract

A systematic, quantitative study of the effect of interface roughness and disorder on the magnetoresistance of $\mathrm{FeCo}\ensuremath{\mid}\mathrm{vacuum}\ensuremath{\mid}\mathrm{FeCo}$ magnetic tunnel junctions is presented based upon parameter-free electronic structure calculations. Surface roughness is found to have a very strong effect on the spin-polarized transport while that of disorder in the leads (leads consisting of a substitutional alloy) is weaker but still sufficient to suppress the huge tunneling magnetoresistance (TMR) predicted for ideal systems.