45 research outputs found
Anisotropic Colossal Magnetoresistance Effects in Fe_{1-x}Cu_xCr_2S_4
A detailed study of the electronic transport and magnetic properties of
FeCuCrS () on single crystals is presented. The
resistivity is investigated for K in magnetic fields up to
14 Tesla and under hydrostatic pressure up to 16 kbar. In addition
magnetization and ferromagnetic resonance (FMR) measurements were performed.
FMR and magnetization data reveal a pronounced magnetic anisotropy, which
develops below the Curie temperature, , and increases strongly
towards lower temperatures. Increasing the Cu concentration reduces this
effect. At temperatures below 35 K the magnetoresistance, , exhibits a strong dependence on the direction of the
magnetic field, probably due to an enhanced anisotropy. Applying the field
along the hard axis leads to a change of sign and a strong increase of the
absolute value of the magnetoresistance. On the other hand the
magnetoresistance remains positive down to lower temperatures, exhibiting a
smeared out maximum with the magnetic field applied along the easy axis. The
results are discussed in the ionic picture using a triple-exchange model for
electron hopping as well as a half-metal utilizing a band picture.Comment: some typos correcte
Spiral spin-liquid and the emergence of a vortex-like state in MnScS
Spirals and helices are common motifs of long-range order in magnetic solids,
and they may also be organized into more complex emergent structures such as
magnetic skyrmions and vortices. A new type of spiral state, the spiral
spin-liquid, in which spins fluctuate collectively as spirals, has recently
been predicted to exist. Here, using neutron scattering techniques, we
experimentally prove the existence of a spiral spin-liquid in MnScS by
directly observing the 'spiral surface' - a continuous surface of spiral
propagation vectors in reciprocal space. We elucidate the multi-step ordering
behavior of the spiral spin-liquid, and discover a vortex-like triple-q phase
on application of a magnetic field. Our results prove the effectiveness of the
- Hamiltonian on the diamond lattice as a model for the spiral
spin-liquid state in MnScS, and also demonstrate a new way to realize a
magnetic vortex lattice.Comment: 10 pages, 11 figure
Accelerating Steered Molecular Dynamics: Toward Smaller Velocities in Forced Unfolding Simulations
Attractive van-der-Waals energies between BMP-2 and the graphite surface.
<p>Attractive van-der-Waals energies between BMP-2 and the graphite surface.</p
Snapshot of the BMP-2 molecule (orientation 1) after 20 ns. a) cMD; b) aMD with sideview (left) and topview (right).
<p>Snapshot of the BMP-2 molecule (orientation 1) after 20 ns. a) cMD; b) aMD with sideview (left) and topview (right).</p
Accelerated Molecular Dynamics Study of the Effects of Surface Hydrophilicity on Protein Adsorption
Simulation of water droplet on graphite surface and fit (black circle) through the droplet surface above 8 Å (red) to exclude the near wall region (blue) according to
<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064883#pone.0064883-Werder1" target="_blank">[<b>27</b>]</a><b>.</b> The green line represents the tangent to the fitted droplet surface in order to determine the contact angle.</p
Secondary structure of BMP-2 before adsorption and at the end of the simulation calculated with dssp [43].
<p>Secondary structure of BMP-2 before adsorption and at the end of the simulation calculated with dssp <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064883#pone.0064883-Kabsch1" target="_blank">[43]</a>.</p
Insulin adsorption on crystalline SiO2: Comparison between polar and nonpolar surfaces using accelerated molecular-dynamics simulations
Conformational space obtained by projection of the trajectory onto the first two eigenvectors of the protein atom covariance matrix.
<p>Each point represents a conformational state at a simulation time shown by the color code.</p