Browsing by Author "Chang, H. -W."

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Effects of post-annealing on the structural and nanomechanical properties of sputter-deposited FePd thin films
(2015-11-05)
Jian, S. -R.
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Chang, H. -W.
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Wang, Y. -W.
;
Yeh, H. -H.
;
Juang, J. -Y.
The effects of post-annealing on the microstructures, surface morphologies and nanomechanical characteristics of FePd thin films are investigated by means of X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and nanoindentation techniques. The FePd thin films were deposited on the glass substrates at room temperature by magnetron sputtering system. Post-annealing was carried out at 500, 600 and 700 degrees C, respectively, resulting in progressive increase of the average grain size and surface roughness of FePd thin films, as well as the improved film crystallinity. XRD results show that FePd thin films are predominantly (111)-oriented, indicating a well-ordered microstructure. The hardness and Young\'s modulus of FePd thin films measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option indicated that both mechanical properties are decreased with increasing the annealing temperature. Furthermore, the relationship between the hardness and films grain size appears to follow closely with the Hall-Petch equation. (C) 2015 Elsevier B.V. All rights reserved.
Nanoindentation Study of FePt Thin Films Deposited by Radio Frequency Magnetron Sputtering
(2016-03)
Chiu, Y. -J.
;
Shen, C. -Y.
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Jian, S. -R.
;
Chang, H. -W.
;
Juang, J. -Y.
The microstructural and nanomechanical properties of Fe0.5Pt0.5 (FePt) thin films deposited on the glass substrates by radio frequency magnetron sputtering were investigated. Specifically, this study focused mainly on the effects of post-annealing on the evolvement of film microstructure and its correlation with the associated nano-mechanical properties. The X-ray diffraction (XRD) results indicated the FePt films were largely equiaxed with the average grain size being increased from similar to 27 nm to similar to 105 nm as the annealing temperature was raised from 400 degrees C to 700 degrees C. The associated film hardness and Young\'s modulus, as derived from the nano-indentation measurements, were decreased from 14.4 +/- 6.8 GPa and 194.2 +/- 9.1 GPa to 8.1 +/- 0.2 GPa and 153.8 +/- 6.5 GPa, respectively. The nano-mechanical properties of the present FePt films were well described by the Hall-Petch relation.