ABSTRACT Devitrification study of Ge15Te82Sb3 is compared to Ge14Te84.5Sb1.5 amorphous alloys using differential scanning calo-rimetry (DSC) and X-ray diffraction; we show tellurium effect in isothermal crystallization phenomena. The DSC traces of Ge15Te82Sb3 fixed at 413?C show the phase separation in the sample with increasing transition temperatures Tg followed by two crystallization temperatures Tc1 and Tc2. This sample is compared to Ge14Te84.5Sb1.5 which crystallized by two transition temperatures and two crystallization temperatures Tc1 and Tc2. By X. Rays diffraction, we show that this behaviour is due to the presence of two phases in the amorphous sample with composition vitreous change during heating sample, the most important first one corresponds to the tellurium crystallization in the hexagonal form with 1.8 eV activation energy. The second correspond essentially to the crystallization of Te+ GeTe phase with 2.1 eV activation energy.
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