14,410 research outputs found
Interaction effects and transport properties of Pt capped Co nanoparticles
We studied the magnetic and transport properties of Co nanoparticles (NPs)
being capped with varying amounts of Pt. Beside field and temperature dependent
magnetization measurements we performed delta-M measurements to study the
magnetic interactions between the Co NPs. We observe a transition from
demagnetizing towards magnetizing interactions between the particles for an
increasing amount of Pt capping. Resistivity measurements show a crossover from
giant magnetoresistance towards anisotropic magnetoresistance
Effect of a Magnetic Field on the Dipole Echo in Glasses with Nuclear Quadrupole Moments
The effect of a magnetic field on the dipole echo amplitude in glasses at
temperatures of about 10 mK caused by nonspherical nuclei with electric
quadrupole moments has been studied theoretically. It has been shown that in
this case, the two-level systems (TLS's) that determine the glass properties at
low temperatures are transformed into more complicated multilevel systems.
These systems have new properties as compared to usual TLS's and, in
particular, exhibit oscillations of electric dipole echo amplitude in magnetic
field. A general formula that describes the echo amplitude in an arbitrary
split TLS has been derived with perturbation theory. Detailed analytic and
numerical analysis of the formula has been performed. The theory agrees
qualitatively and quantitatively well with experimental data.Comment: 5 pages, 3 figure
Large antenna apertures and arrays for deep space communications
Effect of frequency on communications capability, single antennas and arrays, and economic balance between ground station and spacecraft developmen
Telegraph Noise in Coupled Quantum Dot Circuits Induced by a Quantum Point Contact
Charge detection utilizing a highly biased quantum point contact has become
the most effective probe for studying few electron quantum dot circuits.
Measurements on double and triple quantum dot circuits is performed to clarify
a back action role of charge sensing on the confined electrons. The quantum
point contact triggers inelastic transitions, which occur quite generally.
Under specific device and measurement conditions these transitions manifest
themselves as bounded regimes of telegraph noise within a stability diagram. A
nonequilibrium transition from artificial atomic to molecular behavior is
identified. Consequences for quantum information applications are discussed.Comment: 4 pages, 3 figures (as published
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