  We report on quantification and elastic strain mapping in two artificial
BaZrO3/BaTiO3 (BZ/BT) superlattices having periods of 6.6 nm and 11 nm
respectively, grown on (001) SrTiO3 single crystal substrate by pulsed laser
deposition technique. The methodology consists of a combination of
high-resolution scanning transmission electron microscopy and nanobeam electron
diffraction associated with dedicated algorithm for diffraction patterns
processing originally developed for semiconductors to record the strains at
atomic scale. Both in-plane and out-of-plane elastic strains were then
determined at 2 nm spatial resolution and their average values were used to map
the strains along and transverse to the epitaxial growth direction of both
samples to determine its variation along several BZ/BT interfaces. In addition,
the variation of the width of the inter-diffusion BT/BZ interfaces and
intermixing between different layers are estimated. The obtained width average
value measured in these inter-diffusion interfaces vary from 8 to 12% and from
9 to 11% for both superlattices having period of 6.6 nm and 11 nm respectively.
These inter-diffusion interfaces and the inherent elastic strains due to the
confined layers of the superlattices are known to be the most important
parameters, responsible of the change in their functional properties.
