Plan : lattices Characterization of thin films and bulk materials using x-ray and electron scattering V. Pierron-Bohnes IPCMS-GEMME, BP 43, 23 rue du Loess, Strasbourg Cedex 2 1) x-ray and electron - matter interaction 2) real lattice and reciprocal lattice in 3D and 2D samples 3) experimental set-ups 4) studies on single crystals 5) multilayers 6) strains measurements using x-ray scattering and TEM 7) powder scattering measurement 8) texture analysis 9) reflectometry 10) chemical analysis 11) short and long range order measurements

diffracted intensity a powder = small grains + all directions present with the same probability all planes diffract when 2  is convenient example: L1 0 CoPt polarisation integration + structure multiplicity 1 crystal absorption factor Monochromator intensity: for powder no integration in  n

multiplicity? = number of equivalent peaks in the reciprocal space (multiplies the probability to observe this peaks) Examples: cubic lattice: tetragonal lattice Texture: some directions are more present than in a random distribution, in powders: faceted grains can be placed preferentially with the facets // surface in films, a single crystal substrate can induce a texture (epitaxy) an amorphous substrate can also induce a texture (high compacity planes parallel to the surface) Taking into account all the corrections, the peak intensities are compared to determine if there is a texture or not texture ?

absorption correction volume in the beam H: total thickness depends on  if not in  geometry (curved counter) length of trajectory in and out:  x (-  (    )   depends on  if in  geometry z

flat rocking curve ? limitations of the beam limitation of incident beam ? limitation of exit beam ? high  : L I < L E sin  small  : L I > L E sin  high  : L D < L E sin  small  : L D > L E sin   

combination of corrections H << 1/  H >> 1/ 

precise measurement of a lattice parameter for perfect ajustments and without absorption: Bragg law 2d sin  = n effect of a sample not located at the center of the goniometer:  Rsin(2  ’-  ) = Rsin(2  ) +  z R  cos  z  z/Rcos  2d sin  = n →  d sin  + d cos  =0 zz  radius R: detector position 2’2’ sample surface →  d/d= - cotg  →  d/d= -  z / Rsin  is minimum for  /2 (return peaks) to eliminate it: plot as a function of 1  / sin  extrapolated at 0 / / / / / / / / / / / / / / / / / 22 Rsin(2 ’ ) Rsin(2  ) 

precise measurement of a lattice parameter Displacement of Bragg peak due to absorption: where with absorption: without absorption: g

powders (polycrytalline samples) in TEM Example: magnetite in powder Selected-area electron diffraction patterns of a sputtered sandwich (Co3 nmRu1.05 nmCo3 nm) (two printings of the same pattern).

simulation with CarIne: powder XRD example: FePd ordered = nm

simulation with DIFFRACT: powder TEM example: FePd ordered ordered disordered