109,771 research outputs found
Electronic Structure and Bulk Spin Valve Behavior in CaRuO
We report density functional calculations of the magnetic properties and
Fermiology of CaRuO. The ground state consists of ferromagnetic
bilayers, stacked antiferromagnetically. The bilayers are almost but not
exactly half-metallic. In the ferromagnetic state opposite spin polarizations
are found for in-plane and out-of-plane transport. Relatively high out of plane
conductivity is found for the majority spin, which is relatively weakly
conductive in-plane. In the ground state in-plane quantities are essentially
the same, but the out of plane transport is strongly reduced.Comment: 5 page
Origin of ferromagnetism in CsAgF: importance of Ag - F covalency
The magnetic nature of CsAgF, an isoelectronic and isostructural
analogue of LaCuO, is analyzed using density functional calculations.
The ground state is found to be ferromagnetic and nearly half metallic. We find
strong hybridization of Ag- and F- states. Substantial moments reside on
the F atoms, which is unusual for the halides and reflects the chemistry of the
Ag(II) ions in this compound. This provides the mechanism for ferromagnetism,
which we find to be itinerant in character, a result of a Stoner instability
enhanced by Hund's coupling on the F
Spin-charge and spin-orbital coupling effects on spin dynamics in ferromagnetic manganites
Correlation-induced spin-charge and spin-orbital coupling effects on spin
dynamics in ferromagnetic manganites are calculated with realistic parameters
in order to provide a quantitative comparison with experimental results for
spin stiffness, magnon dispersion, magnon damping, anomalous zone-boundary
magnon softening, and Curie temperature. The role of orbital degeneracy,
orbital ordering, and orbital correlations on spin dynamics in different doping
regimes is highlighted.Comment: 19 pages, 9 figure
Should a clinical rotation in haematology be mandatory for undergraduate medical students?
Clinical rotations form the foundation of medical education. Medical students in the UK are offered conventional rotations such as cardiology, surgery and psychiatry as part of their curriculum, but a rotation of haematology is not currently compulsory. This article explores the benefits of a compulsory haematology rotation, and suggests recommendations for its implementation into UK medical school curricula
Feshbach blockade: single-photon nonlinear optics using resonantly enhanced cavity-polariton scattering from biexciton states
We theoretically demonstrate how the resonant coupling between a pair of
cavity-polaritons and a biexciton state can lead to a large single-photon Kerr
nonlinearity in a semiconductor solid-state system. A fully analytical model of
the scattering process between a pair of cavity-polaritons is developed, which
explicitly includes the biexcitonic intermediate state. A dramatic enhancement
of the polariton-polariton interactions is predicted in the vicinity of the
biexciton Feshbach resonance. Application to the generation of non-classical
light from polariton dots is discussed
Time-reversal symmetry breaking in noncentrosymmetric superconductor Re6Hf:further evidence for unconventional behaviour in the alpha-Mn family of materials
The discovery of new families of unconventional superconductors is important
both experimentally and theoretically, especially if it challenges current
models and thinking. By using muon spin relaxation in zero-field, time-reversal
symmetry breaking has been observed in Re6Hf. Moreover, the temperature
dependence of the superfluid density exhibits s-wave superconductivity with an
enhanced electron-phonon coupling. This, coupled with the results from
isostructural Re6Zr, shows that the Re6X family are indeed a new and important
group of unconventional superconductors.Comment: 5 pages, 2 figures Accepted Physical Review B, Rapid Communicatio
Electronic structure and Magnetism in BaMnAs and BaMnSb
We study the properties of ThCrSi structure BaMnAs and
BaMnSb using density functional calculations of the electronic and
magnetic as well experimental measurements on single crystal samples of
BaMnAs. These materials are local moment magnets with moderate band gap
antiferromagnetic semiconducting ground states. The electronic structures show
substantial Mn - pnictogen hybridization, which stabilizes an intermediate spin
configuration for the nominally Mn. The results are discussed in the
context of possible thermoelectric applications and the relationship with the
corresponding iron / cobalt / nickel compounds Ba(Fe,Co,Ni)As
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