Spatial distribution of structural disorder in Co2FeSi films studied by anisotropic magnetoresistance

► Anisotropic magnetoresistance (AMR) as a measure for the phase coexistence in Co2FeSi layers. ► Laterally inhomogeneous distribution of disorder in Co2FeSi films. ► Phenomenological model of the thickness dependence of the AMR amplitude. ► It enables a quantitative estimation of the volume fraction occupied by the disordered B2 phase in Co2FeSi films. ► Results indicate different tetragonal lattice distortions in the B2 and L21 phases of Co2FeSi on GaAs.