2,055,775 research outputs found
Tuning the atomic and domain structure of epitaxial films of multiferroic BiFeO3
Recent works have shown that the domain walls of room-temperature
multiferroic BiFeO3 (BFO) thin films can display distinct and promising
functionalities. It is thus important to understand the mechanisms underlying
domain formation in these films. High-resolution x-ray diffraction and
piezo-force microscopy, combined with first-principles simulations, have
allowed us to characterize both the atomic and domain structure of BFO films
grown under compressive strain on (001)-SrTiO3, as a function of thickness. We
derive a twining model that describes the experimental observations and
explains why the 71o domain walls are the ones commonly observed in these
films. This understanding provides us with a new degree of freedom to control
the structure and, thus, the properties of BiFeO3 thin films.Comment: RevTeX; 4 two-column pages; 4 color figures. Figure 2b does not seem
to display well. A proper version can be found in the source fil
The Automorphism Group of a Domain with an Exponentially Flat Boundary Point
We study the automorphisms group action on a bounded domain in \CC^n having
a boundary point that is exponentially flat. Such a domain typically has a
compact automorphism group. Our results enable us to generate many new
examples.Comment: no figure
PP licensing in nominalizations
In this paper we compare the distribution of PPs introducing external arguments in nominalizations with PPs introducing external arguments in the verbal domain. We show that several mismatches exist between the behavior of PPs in nominalizations and PPs in the verbal domain. This leads us to suggest that while PPs in the verbal domain are licensed by functional structure alone, within the nominal domain, PPs can also be licensed via an interplay of the encyclopaedic meaning of the root involved and the properties of the preposition itself. This second mechanism kicks in in the absence of functional structure
Identification and mechanical control of ferroelastic domain structure in rhombohedral CaMnO
We report on observation of ferroelastic domain structure in single crystals
of multiferroic CaMnO at room temperature. Two types of ferroelastic
domain wall are found, consistent with the material's rhombohedral symmetry
that is reduced from cubic symmetry at higher temperatures. Using Raman
spectroscopy along with other measurements, we develop a systematic method to
determine the microscopic domain orientation. Moreover, we find a switching
behavior of the domains, which allows us to detwin the crystals conveniently at
room temperature using a moderate uniaxial compression. Our result paves the
way for further spectroscopic study and domain engineering in CaMnO.Comment: 7 pages, 4 figure
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