Crystallization kinetics of magnetron-sputtered amorphous CoNbZr thin films

Abstract

For non-isothermal and isothermal annealing, the crystallization kinetics of magnetron sputtered Co 85.5Nb 8.9Zr 5.6 amorphous alloy thin films have been investigated by differential scanning calorimetry measurements. As a result, in the case of non-isothermal crystallization, one distinct exothermic peak is observed at 470 °C, which is due to the crystallization of hcp α-Co. With the Kissinger method, the apparent activation energy was obtained to be 99.82 kJ/mol. By using the Deloy–Ozawa method, the local activation energy of non-isothermal crystallization was calculated. For isothermal crystallization, the Avrami exponents were determined by means of the Johson–Mehl–Avrami equation, which is in the range of 1.19–1.37. Based on an Arrhenius relationship, the local activation energy was analyzed, which yields an average value E c =88.51 kJ/mol. Finally, the local Avrami exponent was used for discussing the details of the nucleation and growth behaviour during the isothermal crystallization.