Journal ArticleDOI
High dielectric constant and tunability of epitaxial srtio3 thin film capacitors
TLDR
In this paper, the dielectric and insulating properties of epitaxial SrTiO3 (STO) thin film capacitors were studied, and the capacitors revealed a large tunability, i.e., a nonlinear e(E) dependence with respect to voltage biasing.Abstract:
The dielectric and insulating properties of epitaxial SrTiO3(STO) thin film capacitors were studied. The films were grown by inverted cylindrical magnetron sputtering in the radio frequency mode on (100) STO substrates which were covered with a (001)-oriented YBa2Cu3O7−x (YBCO) layer as a ground electrode. As a top electrode we used YBCO or Au thin films. A high dielectric constant, e, of up to 5000 was observed at T=80 K. The capacitors revealed a large tunability, i.e., a nonlinear e(E) dependence, with respect to voltage biasing. By applying 3 V, e decreased to 1000 which was 20% of its maximum value. The frequency dependence of e, the temperature dependence of the dielectric loss factor, tan δ, and the direct currency conductivity reflected that variable range hopping via localized states was present and dominated the conduction process in the STO films at low temperatures. The field strength for the electrical breakdown amounted to 300 kV/cm even for rather thin films with a thickness of about 40 nm....read more
Citations
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Journal ArticleDOI
Ferroelectric materials for microwave tunable applications
TL;DR: A review of the properties of ferroelectric materials that are relevant to microwave tunable devices is presented in this article, where the theory of dielectric response of tunable bulk materials and thin films is discussed.
Journal ArticleDOI
Soft-mode hardening in SrTiO3 thin films
Andrei Sirenko,Christian Bernhard,Andrzej Golnik,A. M. Clark,Jianhua Hao,Weidong Si,Xiaoxing Xi +6 more
TL;DR: Far-infrared ellipsometry and low-frequency dielectric measurements in SrTiO3 thin films demonstrate that the Lyddane–Sachs–Teller relation between the optical-phonon eigenfrequencies and the dielectic constant is fully maintained, as is the case in the bulk material.
Journal ArticleDOI
Electronic transport in doped SrTiO 3 : Conduction mechanisms and potential applications
TL;DR: In this paper, an unusual, high mobility, low density, metallic state is established at carrier densities at least as low as $8.5, indicating a distinct crossover in conduction mechanism, perhaps associated with a transition from impurity-band to conduction-band transport.
Journal ArticleDOI
Tunability of the dielectric response of epitaxially strained SrTi O 3 from first principles
TL;DR: In this article, the effect of in-plane strain on the nonlinear dielectric properties of ultrathin epitaxial thin films is calculated using density-functional theory within the local density approximation.
Journal ArticleDOI
Phase transitions and domain structures in strained pseudocubic (100) Sr Ti O 3 thin films
Y. L. Li,Y. L. Li,Somnath Choudhury,J. H. Haeni,Michael D. Biegalski,A. Vasudevarao,Alok Sharan,Hongzhou Ma,Jeremy Levy,Venkatraman Gopalan,Susan Trolier-McKinstry,D. G. Schlom,Quanxi Jia,Long Qing Chen +13 more
TL;DR: In this article, the mutual interactions between a structural transition and a ferroelectric transition were analyzed for different strain states in a pseudocubic (100) ε-dimensional film by examining the equilibrium solutions of the total free energy as a function of polarization, strain and structural order parameter.
References
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Book
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TL;DR: In this paper, the theory of ferroelectricity in terms of soft modes and lattice dynamics is developed and modern techniques of measurement, including X-ray, optic, and neutron scattering, infra-red absorption, and magnetic resonance.
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TL;DR: In the last fifteen years, there has been a noticeable shift towards impure semiconductors -a shift which came about because it is precisely the impurities that are essential to a number of major semiconductor devices.
Journal ArticleDOI
SrTi O 3 : An intrinsic quantum paraelectric below 4 K
Klaus Müller,H. Burkard +1 more
TL;DR: In this article, it was shown that the paraelectric phase stabilizes below 4 K with a very high dielectric constant and the crossover from classical to quantum behavior on lowering the temperature is discussed, and the coupling of the ferroelectric mode to acoustic ones is important.
Journal ArticleDOI
XCVI. Theory of barium titanate
TL;DR: In this article, the theory of the dielectric and crystallographic properties of barium titanate is considered, and the free energy as a function of polarization and strain and making reasonable assumptions about the coefficients is found possible to account for the various crystal transitions.
Journal ArticleDOI
Crystal Stability and the Theory of Ferroelectricity
TL;DR: In this paper, it is shown that the parameters which determine the lattice vibrations of a diatomic ionic crystal may be chosen in such a way that the crystal will exhibit ferroelectric properties, and that anti-ferroelectric transitions may be regarded as the result of an instability of the crystal for a certain normal mode of vibration.