Microstructural and micromagnetic characterization of thin film magnetic tunnel junctions

Abstract

High-resolution electron microscopy, Lorentz microscopy, and off-axis electron holography have been used to characterize magnetic tunnel junctions. Observations in cross section show that the tunnel barriers are slightly narrower and smoother after annealing at temperatures up to 350 °C. The demagnetization of a magnetically hard CoPtCr reference layer through repeated magnetization reversal of a soft layer of either Co or Ni40Fe60 is likely to originate from magnetic fringing fields at Néel walls, which form in the soft layers close to the coercive field.