8,741 research outputs found
Non-uniform thermal magnetization noise in thin films: application to GMR heads
A general scheme is developed to analyze the effect of non-uniform thermal
magnetization fluctuations in a thin film. The normal mode formalism is
utilized to calculate random magnetization fluctuations. The magnetization
noise is proportional to the temperature and inversely proportional to the film
volume. The total noise power is the sum of normal mode spectral noises and
mainly determined by spin-wave standing modes with an odd number of
oscillations. The effect rapidly decreases with increasing mode number. An
exact analytical calcutaion is presented for a two-cell model.Comment: Paper for MMM'01, CB-10, to be published in J. Appl. Phy
Turbulent skin friction and heat-transfer charts adapted from the Spalding and Chi method
Local and average skin friction and heat transfer on flat plates in air - chart
Thermal stability of coupled ferromagnetic and superparamagnetic particles
We consider a single-domain ferromagnetic particle with uniaxial anisotropy
coupled to a single-domain soft ferromagnetic particle (superparamagnetic
particle). The problem of thermally agitated magnetization reversal in this
case can be reduced to the random magnetization dynamics of the first particle
with an effectively larger anisotropy field. The magnetic external field is
also altered in a manner that depends on the sign of the coupling and can be
either enhanced or suppressed.Comment: 3 pages, 2 figures, presented at MMM'0
Is there a Jordan geometry underlying quantum physics?
There have been several propositions for a geometric and essentially
non-linear formulation of quantum mechanics. From a purely mathematical point
of view, the point of view of Jordan algebra theory might give new strength to
such approaches: there is a ``Jordan geometry'' belonging to the Jordan part of
the algebra of observables, in the same way as Lie groups belong to the Lie
part. Both the Lie geometry and the Jordan geometry are well-adapted to
describe certain features of quantum theory. We concentrate here on the
mathematical description of the Jordan geometry and raise some questions
concerning possible relations with foundational issues of quantum theory.Comment: 30 page
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