TOWARDS QUANTITATIVE ELECTRON HOLOGRAPHY OF MAGNETIC THIN-FILMS USINGIN-SITU MAGNETIZATION REVERSAL

An approach based on off-axis electron holography has been developed f or quantifying the magnetization in a sample of unknown local thicknes s with lateral variations in composition. The magnetic field of the ob jective lens is used to reverse the magnetization direction in the sam ple without altering its magnitude, thereby enabling phase changes due to magnetization to be separated from those due to thickness and comp ositional variations. The technique is demonstrated in applications to a lithographically patterned magnetic film on a silicon nitride membr ane and a cross-sectional sample containing a magnetic tunnel junction . The importance of dynamical diffraction effects and fringing fields is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.