Pyroelectric Properties of Ferroelectric Thin Films: Effect of Internal Stresses

2003 ◽  
Vol 784 ◽  
Author(s):  
A. Sharma ◽  
Z.–G. Ban ◽  
S. P. Alpay
Keyword(s):  
Thin Films ◽  
Paraelectric Phase ◽  
Misfit Strain ◽  
Pyroelectric Coefficient ◽  
Ferroelectric Thin Films ◽  
Internal Stresses ◽  
Misfit Dislocations ◽  
Epitaxial Thin Films ◽  
Substrate Selection ◽  
Pyroelectric Response

ABSTRACTA thermodynamic model is employed to analyze the effect of internal stresses on the pyroelectric response of ferroelectric thin films. The pyroelectric coefficient as a function of the misfit strain is calculated for (001) Ba0.6Sr0.4TiO3 epitaxial thin films by taking into account formation of misfit dislocations that relieve epitaxial stresses during deposition. It is shown that the pyroelectric response is highly dependent on the misfit strain in epitaxial thin films. Enhanced pyroelectric coefficient can be achieved by adjusting the misfit strain via substrate selection and film thickness especially in the vicinity of the ferroelectric to paraelectric phase transformation.

Misfit Strain Relaxation by Secondary Phase Formation in Multiferroic BiFeO3 Epitaxial Thin Films

2009 ◽  
Vol 1199 ◽  
Author(s):  
Xue Wang ◽  
Yinlian Zhu ◽  
Xiuliang Ma ◽  
Can Wang ◽  
Huibin Lu
Keyword(s):  
Thin Films ◽  
Strain Relaxation ◽  
Compositional Analysis ◽  
Secondary Phase ◽  
Misfit Strain ◽  
Dark Field ◽  
Misfit Dislocations ◽  
Epitaxial Thin Films ◽  
Annular Dark Field ◽  
Parasitic Phase

AbstractMicrostructures of BiFeO3 (BFO) thin films epitaxially grown on SrRuO3 (SRO) buffered SrTiO3 (STO) (001) substrates by laser molecular beam epitaxy were investigated by means of transmission electron microscopy (TEM). The results showed that the films grown under the oxygen pressures of 1Pa and 0.3Pa, respectively, contain parasitic phase embedded in the BFO phase. The parasitic phase was revealed to be poor in Bi and rich in Fe by high-angle annular dark-field (HAADF) imaging and energy dispersive X-ray spectroscopy (EDS) compositional analysis. In combination with selected area electron diffraction patterns, the parasitic phase was determined to be α-Fe2O3. By lowering oxygen pressure, the density and the size of α-Fe2O3 phase increases whereas the regularity decreases. High resolution TEM images showed that approximately periodic misfit dislocations exist at the interface between the α-Fe2O3 phase and the BFO matrix, indicating that the α-Fe2O3 particles are semi-coherently embedded in the BFO films. Less misfit dislocations were detected at the interfaces between the BFO films and the SRO/STO substrates, implying that the misfit strains in the films may be fully relaxed by the formation of α-Fe2O3 phase.

Pyroelectric response of ferroelectric thin films

2004 ◽  
Vol 95 (7) ◽  
pp. 3618-3625 ◽  
Author(s):  
A. Sharma ◽  
Z.-G. Ban ◽  
S. P. Alpay ◽  
J. V. Mantese
Keyword(s):  
Thin Films ◽  
Ferroelectric Thin Films ◽  
Pyroelectric Response

Domain evolution of tetragonal Pb(ZrxTi1−x) O3 piezoelectric thin films on SrTiO3 (100) surfaces: combined effects of misfit strain and Zr/Ti ratio

2014 ◽  
Vol 2 (29) ◽  
pp. 5836-5841 ◽  
Author(s):  
Qi Yu ◽  
Jing-Feng Li ◽  
Fang-Yuan Zhu ◽  
Jiangyu Li
Keyword(s):  
Thin Films ◽  
Misfit Strain ◽  
Epitaxial Thin Films ◽  
Combined Effects ◽  
Piezoelectric Thin Films ◽  
Domain Evolution ◽  
Ferroelectric Domains ◽  
Substrate Constraint

The ferroelectric domains of tetragonal Pb(ZrxTi1−x)O3 epitaxial thin films have been studied comprehensively to reveal their piezoelectric responses under substrate constraint.

Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

2003 ◽  
Vol 779 ◽  
Author(s):  
Hyung Seok Kim ◽  
Sang Ho Oh ◽  
Ju Hyung Suh ◽  
Chan Gyung Park
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

Misfit Dislocations in Ferroelectric Thin films

2008 ◽  
Vol 14 (S2) ◽  
pp. 240-241 ◽  
Author(s):  
M Arredondo ◽  
M Chi ◽  
M Saunders ◽  
A Petraru ◽  
V Nagarajan ◽  
...  
Keyword(s):  
Thin Films ◽  
New Mexico ◽  
Ferroelectric Thin Films ◽  
Misfit Dislocations

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

scholarly journals Pyroelectric property of SrTiO3/Si ferroelectric-semiconductor heterojunctions near room temperature

2015 ◽  
Vol 05 (04) ◽  
pp. 1550031 ◽  
Author(s):  
Gang Bai ◽  
Dongmei Wu ◽  
Qiyun Xie ◽  
Yanyan Guo ◽  
Wei Li ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Order Parameter ◽  
Thermodynamic Formalism ◽  
Misfit Strain ◽  
Pyroelectric Coefficient ◽  
Pyroelectric Property ◽  
Out Of Plane ◽  
Different Temperatures ◽  
Relationship Of

A nonlinear thermodynamic formalism is developed to calculate the pyroelectric property of epitaxial single domain [Formula: see text] heterojunctions by taking into account the thermal expansion misfit strain at different temperatures. It has been demonstrated that the crucial role was played by the contribution associated with the structure order parameter arising from the rotations of oxygen octahedral on pyroelectricity. A dramatic decrease in the pyroelectric coefficient due to the strong coupling between the polarization and the structure order parameter is found at ferroelectric [Formula: see text]–[Formula: see text] phase transition. At the same time, the thermal expansion mismatch between film and substrate is also found to provide an additional weak decrease of pyroelectricity. The analytic relationship of the out-of-plane pyroelectric coefficient and dielectric constant of ferroelectric phases by considering the thermal expansion of thin films and substrates has been determined for the first time. Our research provides another avenue for the investigation of the pyroelectric effects of ferroic thin films, especially, such as antiferroelectric and multiferroic materials having two or more order parameters.

Crossover between Mott and Efros-Shklovskii variable-range hopping in Sr2IrO4 epitaxial thin films by misfit strain and isovalent doping

2019 ◽  
Vol 126 (18) ◽  
pp. 185101 ◽  
Author(s):  
M. Souri ◽  
J. G. Connell ◽  
J. Nichols ◽  
J. Terzic ◽  
G. Cao ◽  
...  
Keyword(s):  
Thin Films ◽  
Misfit Strain ◽  
Epitaxial Thin Films ◽  
Variable Range Hopping ◽  
Variable Range ◽  
Isovalent Doping
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