Journal ArticleDOI
Theory of the role of covalence in the perovskite-type manganites [La,M(II)]MnO3
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In this article, the theory of double exchange was applied to perovskite-type manganites and detailed qualitative predictions about the magnetic lattice, the crystallographic lattice and the electrical resistivity were made.Abstract:
The theory of semicovalent exchange is reviewed and applied to the perovskite-type manganites $[\mathrm{La}, M(\mathrm{II})]\mathrm{Mn}{\mathrm{O}}_{3}$. With the hypothesis of covalent and semicovalent bonding between the oxygen and manganese ions plus the mechanism of double exchange, detailed qualitative predictions are made about the magnetic lattice, the crystallographic lattice, the electrical resistivity, and the Curie temperature as functions of the fraction of ${\mathrm{Mn}}^{4+}$ present. These predictions are found to be in accord with recent findings from neutron-diffraction and x-ray data as well as with the earlier experiments on this system by Jonker and van Santen.read more
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Ceramic Fuel Cells
TL;DR: Ceramic fuel cells, commonly referred to as solid-oxide fuel cells (SOFCs), are presently under development for a variety of power generation applications as mentioned in this paper, and the critical issues posed by the development of this type of fuel cell are discussed.
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Why Are There so Few Magnetic Ferroelectrics
TL;DR: In this paper, the fundamental physics behind the scarcity of ferromagnetic ferroelectric coexistence was explored and the properties of known magnetically ordered ferro-electric materials were examined.
Journal ArticleDOI
Colossal Magnetoresistant Materials: The Key Role of Phase Separation
TL;DR: In this paper, a large variety of experiments reviewed in detail here contain results compatible with the theoretical predictions, including phase diagrams of manganite models, the stabilization of the charge/orbital/spin ordered half-doped correlated electronics (CE)-states, the importance of the naively small Heisenberg coupling among localized spins, the setup of accurate mean-field approximations, and the existence of a new temperature scale T∗ where clusters start forming above the Curie temperature, the presence of stripes in the system, and many others.
Journal ArticleDOI
Electroluminescence from single monolayers of nanocrystals in molecular organic devices
TL;DR: A hybrid light-emitting diode (LED) that combines the ease of processability of organic materials with the narrow-band, efficient luminescence of colloidal quantum dots (QDs) is demonstrated and a 25-fold improvement in luminescent efficiency is observed.
Book ChapterDOI
Mixed Valence Chemistry-A Survey and Classification
Melvin B. Robin,Peter Day +1 more
TL;DR: In this article, a review is concerned with the neglected class of inorganic compounds, which contain ions of the same element in two different formal states of oxidation, and a number of references cite that many individual examples of this class have been studied, yet they have very rarely been treated as a class, and there has never before, to our knowledge, been a systematic attempt to classify their properties in terms of their electronic and molecular structures.