3,423,457 research outputs found
Doping and disorder in the CoMnAl and CoMnGa half-metallic Heusler alloys
We expand our study on the full-Heusler compounds [I. Galanakis \textit{et
al.}, Appl. Phys. Lett. \textbf{89}, 042502 (2006)] to cover also the case of
doping and disorder in the case of CoMnAl and CoMnGa half-metallic
Heusler alloys. These alloys present a region of very small minority density of
states instead of a real gap. Electronic structure calculations reveal that
doping with Fe and Cr in the case of CoMnAl retains the half-metallicity
contrary to the CoMnGa compound. Cr impurities present an unusual behavior
and the spin moment of the Cr impurity scales almost linearly with the
concentration of Cr atoms contrary to the CoMnZ (Z= Si, Ge, Sn) where it
was almost constant. Half-metallicity is no more preserved for both CoMnAl
and CoMnGa alloys when disorder occurs and there is either excess of Mn or
atoms
A search for ferromagnetism in transition-metal-doped piezoelectric ZnO
We present the results of a computational study of ZnO in the presence of Co
and Mn substitutional impurities. The goal of our work is to identify potential
ferromagnetic ground states within the (Zn,Co)O or (Zn,Mn)O material systems
that are also good candidates for piezoelectricity. We find that, in contrast
to previous results, robust ferromagnetism is not obtained by substitution of
Co or Mn on the Zn site, unless additional carriers (holes) are also
incorporated. We propose a practical scheme for achieving such -type doping
in ZnO
The problem of the co-existence of Arctodiaptomus bacillifer (Koelb.), Acanthodiaptomus denticornis (Wierz.) and Heterocope saliens Lill [Translation from: Memorie dell'Istituto Italiano di Idrobiologia Dott.Marco de Marchi 8 81-94, 1954]
In freshwater environments of modest size and without notable ecological structure, there is usually present only one diaptomid species. When two or more diaptomid species are present in the same habitat, generally their body dimensions are distinctly different. There are only four examples of co-existence of Arctodiaptomus bacillifer (Koelb.) and Acanthodiaptomus denticornis (Wierz.) situated at higher altitudes alpine lakes. The article discusses the results of sampling in the summer of 1953 and the problem of the co-existence of Arctodiaptomus bacillifer, Acanthodiaptomus denticornis and Heterocope saliens
Controlled enhancement or suppression of exchange biasing using impurity -layers
The effects of inserting impurity -layers of various elements into a
Co/IrMn exchange biased bilayer, at both the interface, and at given points
within the IrMn layer a distance from the interface, has been investigated.
Depending on the chemical species of dopant, and its position, we found that
the exchange biasing can be either strongly enhanced or suppressed. We show
that biasing is enhanced with a dusting of certain magnetic impurities, present
at either at the interface or sufficiently far away from the Co/IrMn interface.
This illustrates that the final spin structure at the Co/IrMn interface is not
only governed by interface structure/roughness but is also mediated by local
exchange or anisotropy variations within the bulk of the IrMn
Extreme CO Isotopic Abundances in the ULIRG IRAS 13120-5453: An Extremely Young Starburst or Top-Heavy Initial Mass Function
We present ALMA CO (J=1-0, 3-2 and 6-5), CO (J=1-0) and
CO (J=1-0) observations of the local Ultra Luminous Infrared Galaxy,
IRAS 13120-5453 (dubbed "The Yo-yo"). The morphologies of the three isotopic
species differ, where CO shows a hole in emission towards the center. We
measure integrated brightness temperature line ratios of CO/CO
60 (exceeding 200) and CO/CO 1 in the central
region. Assuming optical thin emission, CO is more abundant than
CO in several regions. The abundances within the central 500 pc are
consistent with enrichment of the ISM via a young starburst (7Myr), a
top-heavy initial mass function or a combination of both.Comment: 7 pages, 3 figures, accepted for publication in ApJ
A New Puzzle for Phenomenal Intentionality
Phenomenal intentionality theories have recently enjoyed significant attention. According to these theories, the intentionality of a mental representation (what it is about) crucially depends on its phenomenal features. We present a new puzzle for these theories, involving a phenomenon called ‘intentional identity’, or ‘co-intentionality’. Co-intentionality is a ubiquitous intentional phenomenon that involves tracking things even when there is no concrete thing being tracked. We suggest that phenomenal intentionality theories need to either develop new uniquely phenomenal resources for handling the puzzle, or restrict their explanatory ambitions
- …