11 research outputs found
Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope
We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in-plane orientation of the magnetic moment was found for film thicknesses exceeding 26 Angstrom. A drastic decrease of the magnetization of the film was detected when the thickness is less than 26 Angstrom
Numerical simulation of magnetization process in antiferromagnetic ferromagnetic bilayer with compensated interface
The properties of antiferromagnetic ferromagnetic bilayer have been studied
using self-consistent mean-field approximation for Heisenberg Hamiltonian. The
perpendicular exchange coupling has been revealed in a bilayer with a
compensated interface. For a uniform antiferromagnetic film a symmetrical
hysteresis loop has been calculated, because the transverse instability
develops within the antiferromagnetic film at certain critical value of
external magnetic field. On the other hand, shifted hysteresis loop with a
finite exchange bias field has been obtained for a non-uniform
antiferromagnetic film consisting of various domains with perpendicular
directions of the easy anisotropy axes.Comment: 6 pages, 4 figure
Controlling depinning and propagation of single domain-walls in magnetic microwires
The magnetization reversal in magnetostrictive amorphous microwires takes place by
depinning and propagation of a single domain wall. This is a consequence of the particular
domain structure determined by the strong uniaxial anisotropy from the reinforcement of
magnetoelastic and shape contributions. In the present study, after an overview on the
current state-of-the art on the topic, we introduce the general behaviour of single walls
in 30 to 40Â cm long Fe-base microwires propagating under homogeneous field. Depending on
the way the walls are generated, we distinguish among three different walls namely,
standard wall, DWst, depinned and propagating
from the wire’s end under homogeneous field which motion is the first one to switch on;
reverse wall, DWrev, propagating from the
opposite end under non-homogeneous field, and defect wall,
DWdef, nucleated around local defect.
Both, DWrev and
DWdef are observed only under large
enough applied field. In the subsequent section, we study the propagation of a wall under
applied field smaller than the switching field. There, we conclude that a minimum field,
Hdep,0, is needed to depin the
DWst, as well as that a minimum field,
Hprop,0, is required for the wall to
propagate long distances. In the last section, we analyse the shape of induced signals in
the pickup coils upon the crossing of the walls and its correlation to the domain walls
shape. We conclude that length and shape of the wall are significantly distorted by the
fact that the wall is typically as long as the measuring coils