165,924 research outputs found
The magnetic characteristics of Galactic OB stars from the MiMeS survey of magnetism in massive stars
The Magnetism in Massive Stars (MiMeS) project represents the largest
systematic survey of stellar magnetism ever undertaken. Based on a sample of
over 550 Galactic B and O-type stars, the MiMeS project has derived the basic
characteristics of magnetism in hot, massive stars. Herein we report
preliminary results.Comment: Proceedings of IAUS 302: Magnetic fields throughout stellar evolutio
Surface-induced magnetism in C-doped SnO
The magnetism of C-doped SnO (001) surfaces is studied using
first-principles calculations. It is found that carbon does not induce
magnetism in bulk SnO when located at the oxygen site, but shows a large
magnetic moment at the SnO (001) surface. The magnetic moment is mainly
contributed by the carbon atoms due to empty minority spins of orbitals and
is localized at the surface and subsurface atoms. No magnetism is observed when
the carbon atom is located at the subsurface oxygen sites. The origin of
magnetism is discussed in the context of surface bonding.Comment: 3 pages, 3 figure
High-field muSR studies of superconducting and magnetic correlations in cuprates above Tc
The advent of high transverse-field muon spin rotation (TF-muSR) has led to
recent muSR investigations of the magnetic-field response of cuprates above the
superconducting transition temperature T_c. Here the results of such
experiments on hole-doped cuprates are reviewed. Although these investigations
are currently ongoing, it is clear that the effects of high field on the
internal magnetic field distribution of these materials is dependent upon a
competition between superconductivity and magnetism. In La_{2-x}Sr_xCuO_4 the
response to the external field above Tc is dominated by heterogeneous spin
magnetism. However, the magnetism that dominates the observed inhomogeneous
line broadening below x ~ 0.19 is overwhelmed by the emergence of a completely
different kind of magnetism in the heavily overdoped regime. The origin of the
magnetism above x ~ 0.19 is currently unknown, but its presence hints at a
competition between superconductivity and magnetism that is reminiscent of the
underdoped regime. In contrast, the width of the internal field distribution of
underdoped YBa_2Cu_3O_y above Tc is observed to track Tc and the density of
superconducting carriers. This observation suggests that the magnetic response
above Tc is not dominated by electronic moments, but rather inhomogeneous
fluctuating superconductivity.Comment: 28 pages, 11 figures, 104 reference
On the Coexistence Magnetism/Superconductivity in the Heavy-Fermion Superconductor CePtSi
The interplay between magnetism and superconductivity in the newly discovered
heavy-fermion superconductor CePtSi has been investigated using the
zero-field SR technique. The SR data indicate that the whole muon
ensemble senses spontaneous internal fields in the magnetic phase,
demonstrating that magnetism occurs in the whole sample volume. This points to
a microscopic coexistence between magnetism and heavy-fermion
superconductivity.Comment: Final version, new figure structure, references correcte
Quantum magnetism with ultracold molecules
This article gives an introduction to the realization of effective quantum
magnetism with ultracold molecules in an optical lattice, reviews experimental
and theoretical progress, and highlights future opportunities opened up by
ongoing experiments. Ultracold molecules offer capabilities that are otherwise
difficult or impossible to achieve in other effective spin systems, such as
long-ranged spin-spin interactions with controllable degrees of spatial and
spin anisotropy and favorable energy scales. Realizing quantum magnetism with
ultracold molecules provides access to rich many-body behaviors, including many
exotic phases of matter and interesting excitations and dynamics.
Far-from-equilibrium dynamics plays a key role in our exposition, just as it
did in recent ultracold molecule experiments realizing effective quantum
magnetism. In particular, we show that dynamical probes allow the observation
of correlated many-body spin physics, even in polar molecule gases that are not
quantum degenerate. After describing how quantum magnetism arises in ultracold
molecules and discussing recent observations of quantum magnetism with polar
molecules, we survey prospects for the future, ranging from immediate goals to
long-term visions.Comment: 21 pages, 6 figures, 1 table. Review articl
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