STUDY OF SOLID-STATE REACTIONS IN NB AL MULTILAYER THIN-FILMS - DIFFERENTIAL SCANNING CALORIMETRY/

Solid state reactions of sputter-deposited Nb/Al multilayer thin films , with periodicities in the range 10-333 nm, have been studied by diff erential scanning calorimetry. The first phase to form upon annealing the films in NbAl3. Constant-heating-rate calorimetric measurements sh ow the presence of two peaks for the formation of this phase, while is othermal scans reveal that the first peak is associated with a nucleat ion and growth type transformation. The formation of NbAl3 is thus int erpreted as a two-stage process of nucleation and growth to coalescenc e (first peak) followed by growth until the consumption of one or both reactants (second peak).