Structural phase transformation observed with in-situ mechanical stress measurement during the growth of amorphous Fe100-xZrx films

Abstract

Fe-100-xZrx thin films (0 < x < 7) grow on top of a Zr base layer in the amorphous phase up to a concentration dependent critical film thickness. At this critical thickness a polymorphous phase transformation of the Fe-100-x-Zrx layer takes place. Zr concentrations higher than 7 at% lead to an amorphous phase for all thicknesses. Here we report on in-situ mechanical stress measurements using an optical deflection technique. Different substrate thicknesses and alloy compositions up to 10 at% Zr were investigated. It is observed that stress builds up only after crystallization. No discontinuity of the deflection is observed during the polymorphous crystallization. The behaviour of stress development is well described by an analytical equation discussed by Cammarata [11].