Soft-mode hardening in SrTiO3 thin films
Article Abstract:
It has been possible to obtain far-infrared ellipsometry and low-frequency dialectric measurements in SrTiO3 thin films. These measurements show that the Lyddane-Sachs-Teller relation between the optical-phonon eigenfrequencies and the dielectric constant is fully maintained. It appears that the substantial reduction of the dielectric constant is a result of a significant change of the lattice dynamical properties. This research has implications for the theories of dielectric response in ferroelectric thin films. The phenomenological theory that links the reduction of permittivity to the interface-modified depolarization field must be balanced against the soft-mode behaviour in thin films.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
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Strain yourself
Article Abstract:
It has been possible to grow thin films of La1.9Sr0.1CuO4 on substrates of slightly smaller lattice constant than the natural value for La1.9Sr0.1CuO4. The La1.9Sr0.1CuO4 adopts this lattice constant, thus placing itself under substantial compressive strain. Strain has an impact on the superconducting transition temperature, and a factor-of-two change in the superconducting transition temperature of the thin films has been recorded. This work may play a role in determining the critical structural parameters that control superconductivity.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Discovery of a useful thin-film dielectric using a composition-spread approach
Article Abstract:
A composition-spread method allowing for the efficient evaluation of materials both with high dielectric constant and high breakdown field, is shown. The approach is applied to the Zr-Sn-Ti-O system and initial results indicated that the performance of the materials are likely to compare with the best alternatives currently intended for integrated-circuit capacitors.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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