1,100 research outputs found
Adiabatic Control of Spin-Wave Propagation using Magnetisation Gradients
Spin waves are of large interest as data carriers for future logic devices.
However, due to the strong anisotropic dispersion relation of dipolar
spin-waves in in-plane magnetised films the realisation of two-dimensional
information transport remains a challenge. Bending of the energy flow is
prohibited since energy and momentum of spin waves cannot be conserved while
changing the direction of wave propagation. Thus, non-linear or non-stationary
mechanisms are usually employed. Here, we propose to use reconfigurable
laser-induced magnetisation gradients to break the system's translational
symmetry. The resulting changes in the magnetisation shift the dispersion
relations locally and allow for operating with different spin-wave modes at the
same frequency. Spin-wave momentum is first transformed via refraction at the
edge of the magnetisation gradient region and then adiabatically modified
inside it. Along these lines the spin-wave propagation direction can be
controlled in a broad frequency range with high efficiency
Cryogenic light detectors with enhanced performance for rare events physics
We have developed and tested a new way of coupling bolometric light detectors
to scintillating crystal bolometers based upon simply resting the light
detector on the crystal surface, held in position only by gravity. This
straightforward mounting results in three important improvements: (1) it
decreases the amount of non-active materials needed to assemble the detector,
(2) it substantially increases the light collection efficiency by minimizing
the light losses induced by the mounting structure, and (3) it enhances the
thermal signal induced in the light detector thanks to the extremely weak
thermal link to the thermal bath. We tested this new technique with a 16 cm
Ge light detector with thermistor readout sitting on the surface of a large
TeO bolometer. The light collection efficiency was increased by greater
than 50\% compared to previously tested alternative mountings. We obtained a
baseline energy resolution on the light detector of 20~eV RMS that, together
with increased light collection, enabled us to obtain the best vs
discrimination ever obtained with massive TeO crystals. At
the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively.
This superb performance meets all of the requirements for the CUPID (CUORE
Upgrade with Particle IDentification) experiment, which is a 1-ton
scintillating bolometer follow up to CUORE.Comment: 6 pages, 4 figure
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