1,721,043 research outputs found
Study of metastable states in the random-field Ising model
No full textThe random-field Ising model (RFIM) provides a convenient framework to investigate complex energy landscapes.
We use an out-of-equilibrium T 1⁄4 0 single spin flip dynamics induced by varying the applied field, starting from locally
stable configurations fsi g: If the configuration considered cannot be reached by a field history from saturation, it is
possible to define a set of connected states which is defined as a basin. A whole hierarchy of basins is found when the
field is increased outside the limits of the initial basin. The resulting structure has the topology of an oriented graph. The
properties of the graph cast new light on properties of the ground state (GS) and the possibility to reach the GS by a
field history from saturation. We have numerically determined the graphs in RFIM realizations of finite size in one
dimension for arbitrary selected states and for the GS. Remarkable differences between them are found in the critical
path of the corresponding graphs, the GS being nearer to the field reachable states than a generic state
A10. Fractals, scaling and the question of self-organized criticality in magnetization processes
No full text
Anomalous behaviour of minor magnetic hysteresis loops in garnet films
No full textThe widths of the minor hysteresis loops were investigated in epitaxially grown uniaxial magnetic garnet films as a function of the maximal magnetic field at the end of the loops. An anomalous behaviour of the minor loops was observed in several samples: the width of a minor loop decreased with increasing maximal field. The phenomenon was interpreted on the basis of domain wall nucleation. Different coercive fields (the domain wall coercive field, H-cw, and the technical coercive field, H-ct) and their relation were also discussed
On the correlation between the widths of minor and major magnetic hysteresis loops
No full textThe widths of the minor and major hysteresis loops were investigated in epitaxially grown uniaxial magnetic garnet
films. It was found that minor loops can be wider than the major loop. This relationship can be turned into the opposite
in the same sample by its proper processing. The phenomenon was interpreted, showing the difference in the character of
the technical coercive force and of domain wall pinning field
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