In-situ and ex-situ study of crystallization behaviour of magnetron sputtered Ni₆₃Zr₃₇ amorphous thin film

ABSTRACT

The stages of crystallization of magnetron sputter-deposited Ni₆₃Zr₃₇ film with mostly amorphous structure have been investigated by differential scanning calorimetry (DSC) and in-situ annealing at 300°C by use of heating stage on a high-resolution transmission electron microscope (HRTEM). These results have been further confirmed by grazing incidence X-ray diffraction analyses of thin film specimens annealed ex-situ at 300°C for various durations. The temperature for crystallization found by DSC has been found to increase from 371°C to 434°C with an increase in heating rate from 3°C/min to 10°C/min, and the apparent activation energy for amorphous to crystalline transformation has been found as ∼260.2 kJ/mol from the Kissinger plot. Studies on HRTEM using in-situ heating stage have shown the crystallization to occur on annealing at 300°C for ∼10 min. Crystallization at a temperature lower than that found by DSC is attributed to structural relaxation with reduction of free volume due to thermal activation. It has been observed that Ni₃Zr forms first due to its large negative enthalpy of formation, and is followed by the formation of Ni-rich solid solution (Ni_ss) grains. HRTEM studies have shown grain rotation with the formation of partial dislocations at Ni₃Zr-Ni_ss interfaces as well as twinning followed by detwinning with dislocation formation in the Ni_ss matrix possibly to reduce the interfacial energy.

KEYWORDS:

• Nickel Zirconium thin films
• annealing
• in-situ heating
• crystallization
• differential scanning calorimetry
• high-resolution transmission electron microscopy

Acknowledgements

The authors would like to thank Mr. Ashok Maikap at the Department of Metallurgical and Materials Engineering for helping in DSC experiment, Mr. Arijit Sarkar of Physics department for assisting in XRD work as well as Mr. Tapas Paul of the Central Research Facility for the technical assistance during TEM cross-section sample preparation.

Disclosure statement

No potential conflict of interest was reported by the authors.