Formation of the orthorhombic phase in CeO2-HfO2 solid solution epitaxial thin films and their ferroelectric properties

2019 ◽  
Vol 114 (23) ◽  
pp. 232902 ◽  
Author(s):  
T. Shiraishi ◽  
S. Choi ◽  
T. Kiguchi ◽  
T. Shimizu ◽  
H. Funakubo ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Ferroelectric Properties ◽  
Orthorhombic Phase ◽  
Epitaxial Thin Films

scholarly journals Intrinsic ferroelectricity in Y-doped HfO2 thin films

2021 ◽  
Author(s):  
Yun Yu ◽  
Pratyush Buragohain ◽  
Ming Li ◽  
Zahra Ahmadi ◽  
Yizhi Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Spontaneous Polarization ◽  
Ferroelectric Properties ◽  
Orthorhombic Phase ◽  
Structural Defects ◽  
Epitaxial Thin Films ◽  
High Crystallinity ◽  
Theoretical Predictions ◽  
Crystal Space

Abstract Ferroelectric HfO2-based materials hold great potential for widespread integration of ferroelectricity into modern electronics due to their robust ferroelectric properties at the nanoscale and compatibility with the existing Si technology. Earlier work indicated that the nanometer crystal grain size was crucial for stabilization of the ferroelectric phase of hafnia. This constraint caused high density of unavoidable structural defects of the HfO2-based ferroelectrics, obscuring the intrinsic ferroelectricity inherited from the crystal space group of bulk HfO2. Here, we demonstrate the intrinsic ferroelectricity in Y-doped HfO2 films of high crystallinity. Contrary to the common expectation, we show that in the 5% Y-doped HfO2 epitaxial thin films, high crystallinity enhances the spontaneous polarization up to a record-high 50 µC/cm2 value at room temperature. The high spontaneous polarization persists at reduced temperature, with polarization values consistent with our theoretical predictions, indicating the dominant contribution from the intrinsic ferroelectricity. The crystal structure of these films reveals the Pca21 orthorhombic phase with a small rhombohedral distortion, underlining the role of the anisotropic stress and strain. These results open a pathway to controlling the intrinsic ferroelectricity in the HfO2-based materials and optimizing their performance in applications.

Effect of Cr substitution on ferrimagnetic and ferroelectric properties of GaFeO3 epitaxial thin films

2018 ◽  
Vol 113 (16) ◽  
pp. 162901 ◽  
Author(s):  
Tsukasa Katayama ◽  
Takuya Osakabe ◽  
Shintaro Yasui ◽  
Yosuke Hamasaki ◽  
Badari Narayana Rao ◽  
...  
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Epitaxial Thin Films ◽  
Cr Substitution

The effect of excess bismuth on the ferroelectric properties of SrBi2Ta2O9 thin films

1997 ◽  
Vol 12 (6) ◽  
pp. 1569-1575 ◽  
Author(s):  
Tze-Chiun Chen ◽  
Tingkai Li ◽  
Xubai Zhang ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Grain Size ◽  
Leakage Current ◽  
Ferroelectric Properties ◽  
Substantial Improvement ◽  
Second Phase ◽  
Limited Solid Solution ◽  
Low Leakage ◽  
Ferroelectric Hysteresis

The effect of excess bismuth on the ferroelectric properties of SrBi2Ta2O9 (SBT) thin films having a perovskite-like layered structure was investigated for excess bismuth contents ranging from 0% to 100%. For the first time, a limited solid solution of SBT and Bi2O3 was shown to exist when the amount of excess Bi was less than 50%. The formation of a solid solution enhanced the grain size and a-b plane orientation of the films, resulting in substantial improvement in the ferroelectric hysteresis properties of the films. On the other hand, when the amount of excess Bi exceeded 50%, Bi2O3 appeared as a second phase which led to high leakage current and poor ferroelectric hysteresis curves. 30–50% excess Bi content was found to be the optimum composition with respect to grain size, crystallographic orientation, and single phase formation. Within this range, SBT films exhibit low leakage current density (˜10−9 A/cm2) and maximum remanent polarization (2Pr ˜12 µC/cm2).

Understanding the formation of the metastable ferroelectric phase in hafnia–zirconia solid solution thin films

Nanoscale ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 716-725 ◽  
Author(s):  
Min Hyuk Park ◽  
Young Hwan Lee ◽  
Han Joon Kim ◽  
Yu Jin Kim ◽  
Taehwan Moon ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Ferroelectric Phase ◽  
Orthorhombic Phase ◽  
Thermodynamics And Kinetics

The origin of the formation of the unexpected ferroelectric orthorhombic phase is systematically examined based on both thermodynamics and kinetics.

scholarly journals Giant flexoelectric effect through interfacial strain relaxation

2012 ◽  
Vol 370 (1977) ◽  
pp. 4944-4957 ◽  
Author(s):  
Daesu Lee ◽  
Tae Won Noh
Keyword(s):  
Thin Films ◽  
Strain Relaxation ◽  
Ferroelectric Properties ◽  
Epitaxial Thin Films ◽  
Epitaxial Thin Film ◽  
Strain Gradients ◽  
Bulk Solids ◽  
Flexoelectric Effect ◽  
Potential Applications ◽  
Interfacial Strain

Interfacial strain gradients in oxide epitaxial thin films provide an interesting opportunity to study flexoelectric effects and their potential applications. Oxide epitaxial thin films can exhibit giant and tunable flexoelectric effects, which are six or seven orders of magnitude larger than those in conventional bulk solids. The strain gradient in an oxide epitaxial thin film can generate an electric field above 1 MV m −1 by flexoelectricity, large enough to affect the physical properties of the film. Giant flexoelectric effects on ferroelectric properties are discussed in this overview of recent experimental observations.

scholarly journals Dielectric anomaly and magnetic response of epitaxial orthorhombic YMnO3 thin films

2007 ◽  
Vol 22 (8) ◽  
pp. 2096-2101 ◽  
Author(s):  
X. Martí ◽  
V. Skumryev ◽  
V. Laukhin ◽  
F. Sánchez ◽  
M.V. García-Cuenca ◽  
...  
Keyword(s):  
Thin Films ◽  
Orthorhombic Phase ◽  
Growth Conditions ◽  
Magnetic Response ◽  
Zero Field ◽  
Epitaxial Thin Films ◽  
Substrate Selection ◽  
Plane Compression ◽  
Zero Field Cooling ◽  
Field Cooling

The structure, magnetic response, and dielectric response of the grown epitaxial thin films of the orthorhombic phase of YMnO3 oxide on Nb:SrTiO3 (001) substrates have been measured. We have found that a substrate-induced strain produces an in-plane compression of the YMnO3 unit cell. The magnetization versus temperature curves display a significant zero-field cooling (ZFC)-field cooling hysteresis below the Néel temperature (TN ≈ 45 K). The dielectric constant increases gradually (up to 26%) below the TN and mimics the ZFC magnetization curve. We argue that these effects could be a manifestation of magnetoelectric coupling in YMnO3 thin films and that the magnetic structure of YMnO3 can be controlled by substrate selection and/or growth conditions.

Ferroelectric properties of manganese doped (Bi1/2Na1/2)TiO3 and (Bi1/2Na1/2)TiO3–BaTiO3 epitaxial thin films

2015 ◽  
Vol 359 ◽  
pp. 923-930 ◽  
Author(s):  
A. Gallegos-Melgar ◽  
D.G. Espinosa-Arbelaez ◽  
F.J. Flores-Ruiz ◽  
A. Lahmar ◽  
J.-L. Dellis ◽  
...  
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Epitaxial Thin Films
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