375 research outputs found
Intrinsic Low Temperature Paramagnetism in B-DNA
We present experimental study of magnetization in -DNA in
conjunction with structural measurements. The results show the surprising
interplay between the molecular structures and their magnetic property. In the
B-DNA state, -DNA exhibits paramagnetic behaviour below 20 K that is
non-linear in applied magnetic field whereas in the A-DNA state, remains
diamagnetic down to 2 K. We propose orbital paramagnetism as the origin of the
observed phenomena and discuss its relation to the existence of long range
coherent transport in B-DNA at low temperature.Comment: 5 pages, 4 figures, submitted to Physical Review Letters October 200
Noise Measurement of Interacting Ferromagnetic Particles with High Resolution Hall Microprobes
We present our first experimental determination of the magnetic noise of a
superspinglass made of < 1 pico-liter frozen ferrofluid. The measurements were
performed with a local magnetic field sensor based on Hall microprobes operated
with the spinning current technique. The results obtained, though preliminary,
qualitatively agree with the theoretical predictions of Fluctuation-Dissipation
theorem (FDT) violation [1].Comment: 4pages, 2 figure
DA MALÁRIA À INSUFICIÊNCIA RENAL AGUDA
In the article attempte was made to show, through a nursing case study how renal function can be seriously affected by a disease. Some priority aspects of nursing treatment are also stressed.Neste artigo tenta-se evidenciar a malária, através do relato de um caso, como uma doença que pode afetar gravemente a função renal. Destacam-se também alguns pontos prioritários no tratamento de enfermagem
Growth of a dynamical correlation length in an aging superspin glass
We report on zero field cooled magnetization relaxation experiments on a
concen- trated frozen ferrofluid exhibiting a low temperature superspin glass
transition. With a method initially developed for spin glasses, we investigate
the field dependence of the relaxations that take place after different aging
times. We extract the typical number of correlated spins involved in the aging
dynamics. This brings important insights into the dynamical correlation length
and its time growth. Our results, consistent with expressions obtained for spin
glasses, extend the generality of these behaviours to the class of superspin
glasses. Since the typical flipping time is much larger for superspins than for
atomic spins, our experiments probe a time regime much closer to that of
numerical simulations
Optical and Thermal-Transport Properties of an Inhomogeneous d-Wave Superconductor
We calculate transport properties of disordered 2D d-wave superconductors
from solutions of the Bogoliubov-de Gennes equations, and show that weak
localization effects give rise to a finite frequency peak in the optical
conductivity similar to that observed in experiments on disordered cuprates. At
low energies, order parameter inhomogeneities induce linear and quadratic
temperature dependencies in microwave and thermal conductivities respectively,
and appear to drive the system towards a quasiparticle insulating phase.Comment: 5 pages,3 figure
Non-generality of the Kadowaki-Woods ratio in correlated oxides
An explicit expression for the Kadowaki-Woods ratio in correlated metals is
derived by invoking saturation of the (high-frequency) Fermi-liquid scattering
rate at the Mott-Ioffe-Regel limit. Significant deviations observed in a number
of oxides are quantitatively explained due to variations in carrier density,
dimensionality, unit cell volume and the number of individual sheets in the
Brillouin zone. A generic re-scaling of the original Kadowaki-Woods plot is
also presented.Comment: 9 pages of text, 1 table, 2 figure
Absence of residual quasiparticle conductivity in the underdoped cuprate YBa2Cu4O8
We report here measurements of the in-plane thermal conductivity K(T) of the
underdoped cuprate YBa2Cu4O8 (Y124) below 1K. K(T) is shown to follow a simple,
phononic T^3 dependence at the lowest temperatures for both current directions,
with a negligible linear, quasiparticle contribution. This observation is in
marked contrast with behavior reported in optimally doped cuprates, and implies
that extended zero-energy (or low energy) low-energy quasiparticles are absent
in YBa2Cu4O8 at low temperatures.Comment: RevTex, 4 pages, 2 figures, Revised versio
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