Control of mechanical response of freestanding PbZr0.52Ti0.48O3 films through texture

The texture of piezoelectric lead zirconate titanate (PZT) thin films plays a key role in their mechanical response and linearity in the stress vs. strain behavior. The open circuit mechanical properties of PZT films with controlled texture varying from 100% (001) to 100% (111) were quantified with...

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Bibliographic Details
Published in:	Applied physics letters 2016-09, Vol.109 (13)
Main Authors:	Das, Debashish, Sanchez, Luz, Martin, Joel, Power, Brian, Isaacson, Steven, Polcawich, Ronald G., Chasiotis, Ioannis
Format:	Article
Language:	eng
Subjects:	Domains Grain orientation Lead titanates Lead zirconate titanates Linearity Mechanical analysis Mechanical properties Micromechanics Modulus of elasticity Piezoelectricity Strain Stresses Substrates Switching Texture Thick films Thin films
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Summary:	The texture of piezoelectric lead zirconate titanate (PZT) thin films plays a key role in their mechanical response and linearity in the stress vs. strain behavior. The open circuit mechanical properties of PZT films with controlled texture varying from 100% (001) to 100% (111) were quantified with the aid of direct strain measurements from freestanding thin film specimens. The texture was tuned using a highly {111}-textured Pt substrate and excess-Pb in the PbTiO3 seed layer. The mechanical and ferroelastic properties of 500 nm thick PZT (52/48) films were found to be strongly dependent on grain orientation: the lowest elastic modulus of 90 ± 2 GPa corresponded to pure (001) texture, and its value increased linearly with the percentage of (111) texture reaching 122 ± 3 GPa for pure (111) texture. These elastic modulus values were between those computed for transversely isotropic textured PZT films by using the soft and hard bulk PZT compliance coefficients. Pure (001) texture exhibited maximum non-linearity and ferroelastic domain switching, contrary to pure (111) texture that exhibited more linearity and the least amount of switching. A micromechanics model was employed to calculate the strain due to domain switching. The model fitted well the non-linearities in the experimental stress–strain curves of (001) and (111) textured PZT films, predicting 17% and 10% of switched 90° domains that initially were favorably aligned with the applied stress in (001) and (111) textured PZT films, respectively.
ISSN:	0003-6951 1077-3118