Models of elastic and inelastic flux switching

The total
\dot{\phi}(t)
waveform of a square-loop magnetic core switched by MMF
F(t)
from negative remanence
\phi = -\phi_{r}
is composed of elastic
\dot{\phi}_{\epsilon}(t)
, decaying inelastic
\dot{\phi}_{i}(t)
, and bell-shaped main inelastic
\dot{\phi}_{ma}(t)
. The worst delta noise in a coincident-current memory core pair is essentially
\dot{\phi}_{i}(t)
. The sources of these components and the static
\phi(F)
curve are explained qualitatively by means of the random variations of the energy gradient vs. domain-wall position: elastic wall displacements and elastic rotation of magnetization induce
\dot{\phi}_{\epsilon}(t)
; minor inelastic wall displacements of essentially constant wall areas induce
\dot{\phi}_{i}(t)
; and major inelastic wall displacements (involving domain collisions) of varying wall areas induce
\dot{\phi}_{ma}(t)
. Semiempirical models for the
\dot{\phi}
components are based on the characteristics of these displacements. A satisfactory agreement is obtained between these models and
\dot{\phi}(t)
oscillograms of a thin ferrite core.