0000000001153040
AUTHOR
A. Cēbers
Unusual domain-wall motion in ferromagnetic semiconductor films with tetragonal anisotropy
International audience; Magnetic field-driven domain-wall propagation in the flow regime is investigated in (Ga, Mn) As ferromagnetic semiconductor layers. Square-shape magnetic domains with an unexpected orientation of their edges, at pi/8 with respect to the anisotropy axes, are found. This is shown to arise from the effect of tetragonal magnetic anisotropy on domain-wall dynamics. Using a one-dimensional model for domain-wall motion and modeling domain growth by contour dynamics the shape and orientation of domains and their field range for existence are well reproduced. These results point to the key role of the vectorial nature of the order parameter in the dynamics of ferromagnetic do…
Three dimensional instability of flexible ferromagnetic filament loop
Dynamics of flexible ferromagnetic filaments in an external magnetic field is considered. We report the existence of a buckling instability of the ferromagnetic filament at the magnetic field reversion, which leads to the formation of a metastable loop. Its relaxation through three dimensional transformation of the configurations is observed experimentally and confirmed by numerical simulations. Bending modulus of the flexible ferromagnetic filaments synthesized by linking micron size core-shell ferromagnetic particles with DNA fragments is estimated by comparison of the parameters of the loops observed in the experiment with theoretical calculations. Formation of the loop and its relaxatio…