TITLE:
Calculating the Phase Transformation Kinetics Using Impedance Spectroscopy for Sb2Te3
AUTHORS:
Carlos Rivera-Rodríguez, Juan Aspiazu Fabián, Raúl Díaz Godoy
KEYWORDS:
Phase Transformation, Sb2Te3, Impedance Spectroscopy
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.4 No.2,
April
29,
2014
ABSTRACT: This paper
describes a simple form, the theory to determine the crystallization fraction
during the phase transformation of a solid, at a constant heating rate, from
data obtained by impedance spectroscopy, where the change of the applied
alternating voltage and measured current are proportional to the
microstructural changes at the sample, corresponding to the volume fraction of
a series layer model of two phases. To determine the volume fraction of each
phase present in the sample, electrical data are obtained: conductivity and
permittivity at DC, which are modeled by an electrical circuit composed by 2-RC,
taking into that the permittivity and the occupied volume correspond to the
filling fraction of each phase. By Cathodic Ersion or Sputtering, samples were
obtained in film form of about 500 in thickness, composed of an alloy of Sb2Te3,
in amorphous phase. To ensure the existence of the phase transformation in the
sample, phase transition tests are performed by changes in: Reflection Optics,
Electrical Resistivity and X-Ray Diffraction, showing clearly the presence of
such a transformation. In the final part of this work, it completely shows the
experimental results, giving a clear and precise idea of the kinetics of phase
transformation of Sb2Te3 alloy, by impedance spectroscopy
technique, which proves to be a simple and practical calculation tool.