18 research outputs found
Spinless impurities in high Tc cuprates: Kondo-like behavior
We compare the effects of in-plane non magnetic Li and Zn
impurities on the normal state of high-T cuprates. Y NMR shows that the
extra hole introduced by Li is not localized in its vicinity. The Tc depression
and induced moments on near neighbour Cu sites of Zn or Li are found identical.
These universal effects of spinless impurities establish the major influence of
the spin perturbation with respect to the charge defect. The susceptibility of
the induced moment measured by Li NMR displays a 1/(T+Theta) behavior. Theta
increases with doping up to about 200 K in the overdoped regime. We attribute
this to a "Kondo like" effect.Comment: To appear in Phys.Rev.Lett. (22 nov. 99) Minor modifications compared
to previous version. 8 pages (4 pages for text + 4 figures
Income Splitting and Gender Equality: The Case for Incentivizing Intra-Household Wealth Transfers
Planck 2013 results. X. HFI energetic particle effects: characterization, removal, and simulation
We describe the detection, interpretation, and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). There are two types of interactions: heating of the 0.1 K bolometer plate; and glitches in each detector time stream. The transientresponses to detector glitch shapes are not simple single-pole exponential decays and fall into three families. The glitch shape for each family has been characterized empirically in flight data and these shapes have been used to remove glitches from the detector time streams. The spectrum of the count rate per unit energy is computed for each family and a correspondence is made to the location on the detector of the particle hit. Most of the detected glitches are from Galactic protons incident on the die frame supporting the micro-machined bolometric detectors. In the Planck orbit at L2, the particle flux is around 5 cm-2 s-1 and is dominated by protons incident on the spacecraft with energy >39 MeV, at a rate of typically one event per second per detector. Different categories of glitches have different signatures in the time stream. Two of the glitch types have a low amplitude component that decays over nearly 1 s. This component produces excess noise if not properly removed from the time-ordered data. We have used a glitch detection and subtraction method based on the joint fit of population templates. The application of this novel glitch subtraction method removes excess noise from the time streams. Using realistic simulations, we find that this method does not introduce signal bias into the Planck data.
Reproduced with permission from Astronomy & Astrophysics, © ESO 201