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The estimation of the signal-to-noise ratio of a nanoparticle
- Source :
- Journal of Physics D: Applied Physics. 34:1612-1616
- Publication Year :
- 2001
- Publisher :
- IOP Publishing, 2001.
-
Abstract
- The quality of a single-domain nanoparticle as a signal processing device is estimated with the aid of the signal-to-noise ratio (SNR) characteristic. In the absence of an external field, the magnetic moment of a uniaxial particle flips spontaneously between two anti-parallel equilibrium positions ensuing customary superparamagnetism. On imposition of an external ac field, it, together with random noise, influences the magnetic switching and the SNR can be found in the framework of micromagnetic theory. The main material parameters essentially involved in the resulting expression are, the N´ eel relaxation time, τN , the precessional decay time, τ0, and also the magnetic viscosity coefficient, ηm. In the paper we find these quantities by measuring the complex magnetic susceptibility as a function of frequency and polarizing field. Using these data, we estimate the SNR for the nanometre-size grains of a cobalt ferrofluid.
- Subjects :
- Signal processing
Ferrofluid
Acoustics and Ultrasonics
Magnetic moment
Condensed matter physics
Field (physics)
Chemistry
Condensed Matter Physics
Magnetic susceptibility
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Condensed Matter::Materials Science
Signal-to-noise ratio
Micromagnetics
Superparamagnetism
Subjects
Details
- ISSN :
- 13616463 and 00223727
- Volume :
- 34
- Database :
- OpenAIRE
- Journal :
- Journal of Physics D: Applied Physics
- Accession number :
- edsair.doi...........279a0a615a4f0639e08ed7a1f4e106f2