1,768 research outputs found
A hierarchy of bound states in the 1D ferromagnetic Ising chain CoNbO investigated by high resolution time-domain terahertz spectroscopy
Kink bound states in the one dimensional ferromagnetic Ising chain compound
CoNbO have been studied using high resolution time-domain terahertz
spectroscopy in zero applied magnetic field. When magnetic order develops at
low temperature, nine bound states of kinks become visible. Their energies can
be modeled exceedingly well by the Airy function solutions to a 1D
Schr\"odinger equation with a linear confining potential. This sequence of
bound states terminates at a threshold energy near two times the energy of the
lowest bound state. Above this energy scale we observe a broad feature
consistent with the onset of the two particle continuum. At energies just below
this threshold we observe a prominent excitation that we interpret as a novel
bound state of bound states -- two pairs of kinks on neighboring chains
Roles of Bond Alternation in Magnetic Phase Diagram of RMnO3
In order to investigate nature of the antiferromagnetic structures in
perovskite RMnO3, we study a Heisenberg J1-J2 model with bond alternation using
analytical and numerical approaches. The magnetic phase diagram which includes
incommensurate spiral states and commensurate collinear states is reproduced.
We discuss that the magnetic structure with up-up-down-down spin configuration
(E-type structure) and the ferroelectricity emerge cooperatively to stabilize
this phase. Magnetoelastic couplings are crucial to understand the magnetic and
electric phase diagram of RMnO3.Comment: 5 pages, 6 figure
PUK13 LOWER MENTAL HEALTH SCORES MEASURED USING THE SF-36 HEALTH SURVEY IS AN INDEPENDENT PREDICTOR OF MORTALITY IN YOUNGER PATIENTS RENAL REPLACEMENT THERAPY
Electric-dipole active two-magnon excitation in {\textit{ab}} spiral spin phase of a ferroelectric magnet GdTbMnO
A broad continuum-like spin excitation (1--10 meV) with a peak structure
around 2.4 meV has been observed in the ferroelectric spiral spin phase of
GdTbMnO by using terahertz (THz) time-domain spectroscopy.
Based on a complete set of light-polarization measurements, we identify the
spin excitation active for the light vector only along the a-axis, which
grows in intensity with lowering temperature even from above the magnetic
ordering temperature but disappears upon the transition to the -type
antiferromagnetic phase. Such an electric-dipole active spin excitation as
observed at THz frequencies can be ascribed to the two-magnon excitation in
terms of the unique polarization selection rule in a variety of the
magnetically ordered phases.Comment: 11 pages including 3 figure
Nanospintronics with carbon nanotubes
One of the actual challenges of spintronics is the realization of a
spin-transistor allowing to control spin transport through an electrostatic
gate. In this review, we report on different experiments which demonstrate a
gate control of spin transport in a carbon nanotube connected to ferromagnetic
leads. We also discuss some theoretical approaches which can be used to analyze
spin transport in these systems. We emphasize the roles of the gate-tunable
quasi-bound states inside the nanotube and the coherent spin-dependent
scattering at the interfaces between the nanotube and its ferromagnetic
contacts.Comment: 35 pages, 15 figures, some figures in gi
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