Size effect on the electromechanical coupling factor of a thin piezoelectric film due to a nonlocal polarization law

Yang, Jiashi; Mao, Scott X.; Yan, Kexin; Soh, Ai‐Kah

doi:10.1016/j.scriptamat.2005.12.030

Cited by 7 publications

(9 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We note that Yang et al 29,30 have investigated the use of non-local polarization law to study the size effects and electromechanical coupling in thin film nanocapacitors. Recently, Kalinin and Meunier 31 have investigated flexoelectricity in low-dimensional nanostructures.…”

Section: Flexoelectricity and Consequences For Dead-layer In Nanomentioning

confidence: 99%

Understanding the origins of the intrinsic dead layer effect in nanocapacitors

2009

View full text Add to dashboard Cite

Thin films of high-permittivity dielectrics are considered ideal candidates for realizing high charge density nanoscale capacitors for use in next generation energy storage and nanoelectronics applications. The experimentally observed capacitance of such film nanocapacitors is, however, an order of magnitude lower than expected. This dramatic drop in capacitance is attributed to the so-called "dead layer" -a low-permittivity layer at the metal-dielectric interface in series with the high-permittivity dielectric. Recent evidence suggests that this effect is intrinsic in the sense that its emergence is evident even in "perfectly" fabricated structures. The exact nature of the intrinsic dead-layer and the reasons for its origin still remain somewhat unclear. Based on insights gained from recently published ab initio work on SrRuO 3 /SrTiO 3 /SrRuO 3 and our first principle simulations on Au/MgO/Au and Pt/MgO/Pt nanocapacitors, we construct an analytical model that isolates the contributions of various physical mechanisms to the intrinsic dead layer. In particular we argue that strain-gradients automatically arise in very thin films even in complete absence of external strain inducers and, due to flexoelectric coupling, are dominant contributors to the dead layer effect. Our theoretical results compare well with existing, as well as our own, ab initio calculations and suggest that inclusion of flexoelectricity is essential for qualitative reconciliation of atomistic results. Our results also hint at some novel remedies for mitigating the dead layer effect.

show abstract

Section: Flexoelectricity and Consequences For Dead-layer In Nanomentioning

confidence: 99%

Understanding the origins of the intrinsic dead layer effect in nanocapacitors

2009

View full text Add to dashboard Cite

show abstract

“…As we discussed previously, the h111i orientation of PZT films arises from the epitaxial growth on the (111) Pt buffer layer. It is assumed that the electric domains in the film align under a poling voltage, leading to a substantial increase in polarization 32 and piezoelectric properties. As a result, a piezoelec-…”

Section: Resultsmentioning

confidence: 99%

Epitaxial growth of Pb(Zr0.53Ti0.47)O3 films on Pt coated magnetostrictive amorphous metallic substrates toward next generation multiferroic heterostructures

Chen

Yang

et al. 2012

Journal of Applied Physics

View full text Add to dashboard Cite

Piezoelectric films of Pb(Zr0.53Ti0.47)O3 (PZT) were deposited by pulsed laser deposition onto metallic magnetostrictive substrates. In order to optimize the growth of PZT films, a buffer layer of Pt was employed, as well as variation of deposition temperature, pressure, and laser energy. Room temperature θ-2θ x-ray diffraction measurements indicate all diffraction features correspond to reflections indexed to a single PZT phase of space group P4mm. Scanning electron microscopy images reveal pinhole-free dense films of pyramidal shaped crystal arrangements whose orientation and size were controlled by variation of oxygen pressures during deposition. The resulting PZT films had a value of d33 ∼ 46 pm/V representing a 53% increase over previous efforts to realize a piezoelectric/Metglas™ film heterostructure.

show abstract

“…In this section we examine the effect of nonlocality on electromechanical coupling factors of thin films (see Figure 8.5) [9]. The surfaces of the film are electroded.…”

Section: Electromechanical Coupling By Nonlocal Theorymentioning

confidence: 99%

Nonlocal and Gradient Effects

Yang

2009

Special Topics in the Theory of Piezoelectricity

View full text Add to dashboard Cite

Classical continuum theories such as elasticity, electrostatics, and piezoelectricity are the long-wave and low-frequency limits of the equations of lattice dynamics. The partial differential equations of these continuum theories can be obtained from the finite difference equations of lattice dynamics by Taylor expansions and truncations. The equations of classical continuum theories are accurate for phenomena with a characteristic length much larger than microscopic characteristic lengths, for example, the distance between neighboring atoms in a lattice. When the characteristic length of a problem is not much larger than the microscopic characteristic length, classical continuum theories do not predict results consistent with lattice dynamics, and hence are no longer valid. For example, lattice waves are dispersive but the theory of elasticity only predicts nondispersive plane waves which are the long wave limit of lattice waves.There are different ways to modify the classical continuum theories so that their range of applicability can be extended to problems with smaller characteristic lengths, with results closer to lattice dynamics in a wider range of wave lengths.One is to generalize the constitutive relations in classical continuum theories from local to nonlocal [1][2][3][4][5]. In classical continuum theories, the constitutive relations are for stress and strain (or electric field and polarization) at the same material point, with a zero interaction distance (local theories). These constitutive relations neglect the microstructure of real materials and lead to macroscopic theories for large characteristic lengths. In nonlocal constitutive relations, a finite microscopic interaction distance is

show abstract

Size effect on the electromechanical coupling factor of a thin piezoelectric film due to a nonlocal polarization law

Cited by 7 publications

References 11 publications

Understanding the origins of the intrinsic dead layer effect in nanocapacitors

Understanding the origins of the intrinsic dead layer effect in nanocapacitors

Epitaxial growth of Pb(Zr0.53Ti0.47)O3 films on Pt coated magnetostrictive amorphous metallic substrates toward next generation multiferroic heterostructures

Nonlocal and Gradient Effects

Contact Info

Product

Resources

About