542 research outputs found
Towards achieving strong coupling in 3D-cavity with solid state spin resonance
We investigate the microwave magnetic field confinement in several microwave
3D-cavities, using 3D finite-element analysis to determine the best design and
achieve strong coupling between microwave resonant cavity photons and solid
state spins. Specifically, we design cavities for achieving strong coupling of
electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in
diamond. We report here a novel and practical cavity design with a magnetic
filling factor of up to 4 times (2 times higher collective coupling) than
previously achieved using 1D superconducting cavities with small mode volume.
In addition, we show that by using a double-split resonator cavity, it is
possible to achieve up to 200 times better cooperative factor than the
currently demonstrated with NV in diamond. These designs open up further
opportunities for studying strong and ultra-strong coupling effects on spins in
solids using alternative systems with a wider range of design parameters.Comment: 20 pages, 9 figure
Controlling the Frequency-Temperature Sensitivity of a Cryogenic Sapphire Maser Frequency Standard by Manipulating Fe3+ Spins in the Sapphire Lattice
To create a stable signal from a cryogenic sapphire maser frequency standard,
the frequency-temperature dependence of the supporting Whispering Gallery mode
must be annulled. We report the ability to control this dependence by
manipulating the paramagnetic susceptibility of Fe3+ ions in the sapphire
lattice. We show that the maser signal depends on other Whispering Gallery
modes tuned to the pump signal near 31 GHz, and the annulment point can be
controlled to exist between 5 to 10 K depending on the Fe3+ ion concentration
and the frequency of the pump. This level of control has not been achieved
previously, and will allow improvements in the stability of such devices.Comment: 17 pages, 10 figure
Effect of Sr substitution on superconductivity in Hg2(Ba1-ySry)2YCu2O8-d (part2): bond valence sum approach of the hole distribution
The effects of Sr substitution on superconductivity, and more particulary the
changes induced in the hole doping mechanism, were investigated in
Hg2(Ba1-ySry)2YCu2O8-d by a "bond valence sum" analysis with Sr content from y
= 0.0 to y = 1.0. A comparison with CuBa2YCu2O7-d and Cu2Ba2YCu2O8 systems
suggests a possible explanation of the Tc enhancement from 0 K for y = 0.0 to
42 K for y = 1.0. The charge distribution among atoms of the unit cell was
determined from the refined structure, for y = 0.0 to 1.0. It shows a charge
transfer to the superconducting CuO2 plane via two doping channels pi(1) and
pi(2), i.e. through O2(apical)-Cu and Ba/Sr-O1 bonds respectively.Comment: 13 pages, 5 figures, accepted for publication in Journal of Physics:
Condensed Matte
Statistics of the main purse seine fleets fishing in the Indian Ocean (1981-2010).
This document presents a summary of the statistics of French, Spanish, Italian, Seychelles
and EU related NEI purse seine fleets fishing in the Indian Ocean since 1981: effort, catch by
species and fishing type (log and free swimming schools), catch per unit of effort, sampling
and mean weights for the main species.
Since 2002, data from the European fleet (France and Spain) are collected within the
framework of the EU “Data Collection Regulation” (DCR, Reg. 1543/2000 and 1639/2001),
followed in 2008 by the “Community framework for the collection, management and use of
data in the fisheries sector and support for scientific advice regarding the Common Fisheries
Policy” (DCF, Reg 199/2008 and 665/2008). Data from other fleets are collected by SFA
(Seychelles Fishing Authority).
Data processing (species composition and size distribution) is done collectively for the whole
fishery
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