“Time-resolved motion of a single domain wall controlled by a local tunable barrier”
Esther Calle, Manuel Vázquez and Rafael Pérez del Real
J. Magn. Magn. Mater., 2019, 166142
DOI: https://doi.org/10.1016/j.jmmm.2019.166093
We report on the time-resolved dynamics of a single magnetic domain wall (DW) under the influence of a tunable barrier in a Fe-rich microwire. The energy barrier was created by applying a local magnetic field antiparallel to the uniform driving field used to depin and propagate the DW along the wire. This originates the braking and eventually the trapping of the DW depending on the magnitude of the antiparallel local field. The motion of the DW through the local field becomes stochastic for minimum magnetic field values close to the measured friction field (Hfr=24.4A/m). This phenomenon is caused by fluctuations in the pinning field associated to the different
types of local defects and residual stress existing in the wire. The probability for the DW to overcome the barrier has been estimated for different values of the local field. When the minimum applied field is lower than the fluctuating friction field the DW is always trapped.
In the figure we show the time-resolved DW velocity for Hprim=90.5A/m and Hmin=35.6A/m. Different colors mean the different stages during the nucleation and propagation of the DW: orange the nucleation and acceleration, pale pink the movement at steady velocity, blue the braking by the local field and green the braking and stopping when it is close to the end of the primary coil.
This work has been supported by the Spanish National Research Council under CSIC Project No. 201760E040 and by Comunidad Autónoma de Madrid under Project S2018/NMT-4321 NANOMAGCOST