74 research outputs found
An integrated study of earth resources in the State of California based on ERTS-1 and supporting aircraft data, volume 1
There are no author-identified significant results in this report
An integrated study of earth resources in the State of California using remote sensing techniques
The author has identified the following significant results. The supply, demand, and impact relationships of California's water resources as exemplified by the Feather River project and other aspects of the California Water Plan are discussed
An integrated study of earth resources in the state of California using remote sensing techniques
The University of California has been conducting an investigation which seeks to determine the usefulness of modern remote sensing techniques for studying various components of California's earth resources complex. Most of the work has concentrated on California's water resources, but with some attention being given to other earth resources as well and to the interplay between them and California's water resources
An integrated study of earth resources in the State of California based on ERTS-1 and supporting aircraft data
There are no author-identified significant results in this report
A Duality Between Unidirectional Charge Density Wave Order and Superconductivity
This paper shows the existence of a duality between an unidirectional charge
density wave order and a superconducting order. This duality predicts the
existence of charge density wave near a superconducting vortex, and the
existence of superconductivity near a charge density wave dislocation.Comment: Main results are the same, but the presentation is significantly
modified. To appear in Physical Review Letter
Inhomogeneous magnetism in single crystalline SrCuIrO: Implications to phase-separation concepts
The single crystalline form of an insulator, SrCuIrO, is
shown to exhibit unexpectedly more than one magnetic transition (at 5 and 19 K)
with spin-glass-like magnetic susceptibility behaviour. On the basis of this
finding, viz., inhomogeneous magnetism in a chemically homogeneous material, we
propose that the idea of "phase- separation" described for manganites [1] is
more widespread in different ways. The observed experimental features enable us
to make a comparison with the predictions of a recent toy model [2] on {\it
magnetic} phase separation in an insulating environment.Comment: 4 pages, 4 figure
Local Ferromagnetism in Microporous Carbon with the Structural Regularity of Zeolite Y
Magnetization M(H,T) measurements have been performed on microporous carbon
(MC) with a three-dimensional nano-array structure corresponding to that of a
zeolite Y supercage. The obtained results unambiguously demonstrate the
occurrence of high-temperature ferromagnetism in MC, probably originating from
a topological disorder associated with curved graphene sheets. The results
provide evidence that the ferromagnetic behavior of MC is governed by isolated
clusters in a broad temperature range, and suggest the occurrence of
percolative-type transition with the temperature lowering. A comparative
analysis of the results obtained on MC and related materials is given.Comment: To be published in Physical Review B (2003
Dopant-dependent impact of Mn-site doping on the critical-state manganites: R0.6Sr0.4MnO3 (R=La, Nd, Sm, and Gd)
Versatile features of impurity doping effects on perovskite manganites,
SrMnO, have been investigated with varying the doing
species as well as the -dependent one-electron bandwidth. In
ferromagnetic-metallic manganites (=La, Nd, and Sm), a few percent of Fe
substitution dramatically decreases the ferromagnetic transition temperature,
leading to a spin glass insulating state with short-range charge-orbital
correlation. For each species, the phase diagram as a function of Fe
concentration is closely similar to that for SrMnO
obtained by decreasing the ionic radius of site, indicating that Fe doping
in the phase-competing region weakens the ferromagnetic double-exchange
interaction, relatively to the charge-orbital ordering instability. We have
also found a contrastive impact of Cr (or Ru) doping on a spin-glass insulating
manganite (=Gd). There, the impurity-induced ferromagnetic magnetization is
observed at low temperatures as a consequence of the collapse of the inherent
short-range charge-orbital ordering, while Fe doping plays only a minor role.
The observed opposite nature of impurity doping may be attributed to the
difference in magnitude of the antiferromagnetic interaction between the doped
ions.Comment: 7 pages, 6 figure
Colossal Magnetoresistance is a Griffiths Singularity
It is now widely accepted that the magnetic transition in doped manganites
that show large magnetoresistance is a type of percolation effect. This paper
demonstrates that the transition should be viewed in the context of the
Griffiths phase that arises when disorder suppresses a magnetic transition.
This approach explains unusual aspects of susceptibility and heat capacity data
from a single crystal of LaCaMnOComment: 4 page
Glass Transition in the Polaron Dynamics of CMR Manganites
Neutron scattering measurements on a bilayer manganite near optimal doping
show that the short-range polarons correlations are completely dynamic at high
T, but then freeze upon cooling to a temperature T* 310 K. This glass
transition suggests that the paramagnetic/insulating state arises from an
inherent orbital frustration that inhibits the formation of a long range
orbital- and charge-ordered state. Upon further cooling into the
ferromagnetic-metallic state (Tc=114 K), where the polarons melt, the diffuse
scattering quickly develops into a propagating, transverse optic phonon.Comment: 4 pages, 4 figures. Physical Review Letters (in Press
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