727 research outputs found
Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}
Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around
1/3 was investigated by neutron diffraction experiments. When the stripe order
is formed at high temperature, incommensurability \epsilon of the stripe order
has a tendency to show the value close to 1/3 for the samples with x at both
sides of 1/3. With decreasing temperature, however, \epsilon becomes close to
the value determined by the linear relation of \epsilon = n_h, where n_h is a
hole concentration. This variation of the \epsilon strongly affects the
character of the stripe order through the change of the carrier densities in
stripes and antiferromagnetic domains.Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev.
Novel stripe-type charge ordering in the metallic A-type antiferromagnet Pr{0.5}Sr{0.5}MnO{3}
We demonstrate that an A-type antiferromagnetic (AFM) state of
Pr{0.5}Sr{0.5}MnO{3} exhibits a novel charge ordering which governs the
transport property. This charge ordering is stripe-like, being characterized by
a wave vector q ~ (0,0,0.3) with very anisotropic correlation parallel and
perpendicular to the stripe direction. This charge ordering is specific to the
manganites with relatively wide one-electron band width (W) which often exhibit
a metallic A-type AFM state, and should be strictly distinguished from the
CE-type checkerboard-like charge ordering which is commonly observed in
manganites with narrower W such as La{1-x}Ca{x}MnO{3} and Pr{1-x}Ca{x}MnO{3}.Comment: REVTeX4, 5 pages, 4 figure
The Effect of - Magnetic Coupling in Multiferroic MnO Crystals
We have established detailed magnetoelectric phase diagrams of
(EuY)TbMnO () and
(Eu,Y)GdMnO (), whose average ionic radii of
-site (: rare earth) cations are equal to that of Tb, in order to
reveal the effect of rare earth 4 magnetic moments on the magnetoelectric
properties. In spite of the same -site ionic radii, the magnetoelectric
properties of the two systems are remarkably different from each other. A small
amount of Tb substitution on sites () totally destroys
ferroelectric polarization along the a axis (), and an increase in Tb
concentration stabilizes the phase. On the other hand, Gd substitution
() extinguishes the phase, and slightly suppresses the
phase. These results demonstrate that the magnetoelectric properties of
MnO strongly depend on the characteristics of the rare earth 4
moments.Comment: 10 pages, 5 figures Submitted to Journal of the Physical Society of
Japa
Influence of Mg, Ag and Al substitutions on the magnetic excitations in the triangular-lattice antiferromagnet CuCrO2
Magnetic excitations in CuCrO, CuCrMgO,
CuAgCrO, and CuCrAlO have been
studied by powder inelastic neutron scattering to elucidate the element
substitution effects on the spin dynamics in the Heisenberg triangular-lattice
antiferromagnet CuCrO. The magnetic excitations in
CuCrMgO consist of a dispersive component and a flat
component. Though this feature is apparently similar to CuCrO, the energy
structure of the excitation spectrum shows some difference from that in
CuCrO. On the other hand, in CuAgCrO and
CuCrAlO the flat components are much reduced, the
low-energy parts of the excitation spectra become intense, and additional
low-energy diffusive spin fluctuations are induced. We argued the origins of
these changes in the magnetic excitations are ascribed to effects of the doped
holes or change of the dimensionality in the magnetic correlations.Comment: 7 pages, 5 figure
Responses of ring widths and maximum densities of Larix gmelinii to climate on contrasting north- and south-facing slopes in central Siberia
The original publication is available at www.springerlink.com.ArticleEcological Research. 22(4):582-592 (2007)journal articl
Climatic responses of tree-ring widths of Larix gmelinii on contrasting north- and south-facing slopes in central Siberia
The original publication is available at www.springerlink.com.ArticleJournal of Wood Science. 53(2): 87-93 (2007)journal articl
Electron- and Hole-Doping Effects on -site Ordered NdBaMnO
We have investigated electron- and hole-doping effects on -site ordered
perovskite manganite NdBaMnO, which has the -type (layered)
antiferromagnetic (AFM) ground state. Electrons (holes) are introduced by
partial substitution of Ba (Nd) with Nd (Ba).
Electron-doping generates ferromagnetic (FM) clusters in the -type AFM
matrix. With increasing the electron-doping level, the volume fraction of the
FM phase or the number of the FM clusters is abruptly increasing. In contrast,
the -type AFM phase is robust against the hole-doping, and no FM correlation
is observed in the hole-doped NdBaMnO.Comment: 8 pages, 5 figures, to be published in Journal of the Physical
Society of Japa
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