42,651 research outputs found
The Nature and Validity of the RKKY limit of exchange coupling in magnetic trilayers
The effects on the exchange coupling in magnetic trilayers due to the
presence of a spin-independent potential well are investigated. It is shown
that within the RKKY theory no bias nor extra periods of oscillation associated
with the depth of the well are found, contrary to what has been claimed in
recent works. The range of validity of the RKKY theory is also discussed.Comment: 10, RevTe
Noise characterization of an atomic magnetometer at sub-millihertz frequencies
Noise measurements have been carried out in the LISA bandwidth (0.1 mHz to
100 mHz) to characterize an all-optical atomic magnetometer based on nonlinear
magneto-optical rotation. This was done in order to assess if the technology
can be used for space missions with demanding low-frequency requirements like
the LISA concept. Magnetometry for low-frequency applications is usually
limited by noise and thermal drifts, which become the dominant
contributions at sub-millihertz frequencies. Magnetic field measurements with
atomic magnetometers are not immune to low-frequency fluctuations and
significant excess noise may arise due to external elements, such as
temperature fluctuations or intrinsic noise in the electronics. In addition,
low-frequency drifts in the applied magnetic field have been identified in
order to distinguish their noise contribution from that of the sensor. We have
found the technology suitable for LISA in terms of sensitivity, although
further work must be done to characterize the low-frequency noise in a
miniaturized setup suitable for space missions.Comment: 11 pages, 12 figure
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