Dynamical properties of magnetization reversal in an ultrathin film

Magnetic domain wall creep in the presence of an effective interlayer coupling field

“…Therefore, a more reasonable value for the coupling field as determined from the velocity experiments is H wall J ¼ 4:9 AE 1:2 Oe which is consistent, within experimental error, with H hyst J . This consistency is not unexpected since H hyst J has been measured at a rather low field sweep rate for which wall propagation is expected to be the dominant reversal process [20,29].…”

Dynamic Hysteresis Loop of a Ferromagnetic Layer: Effect of the High Second Order of the Anisotropy Constant.

“…A method to probe reversal dynamics and to determine the relevant mechanism in the reversal process is to measure dynamics hysteresis loops and to examine the dynamic coercivity dependence of the field sweep rate. We measured the dynamic hysteresis loops (Fig.2) comparison with the previous studies made on these kinds of systems [7], this could also be attribute to a probable purpose of remanence of the coil. However, the increase of the coercivities accompanied by widening transitions indicate that the magnetization reversal process is thermally activated.…”

“…where M s is the saturation magnetization, [7] through their works done on Au/Co/Au. On the other hand the τ(H=0) values are weaker than those found in bibliography [9].…”

“…If the first is currently assumed to be thermally activated process with single [6] or distribution of energy barrier, the last can be described by thermally activated process or more complex viscous motions [7]. The predominance of one process against the others is governed by the variation rate of the magnetic applied field and the micro-structure of the material.…”

Training and recovery behaviors of exchange bias in FeNi/Cu/Co/FeMn spin valves at high field sweep rates

“…Because most of studies are limited to long timescales (> 1s), by the usually quite long measurement time in magnetometry approaches, the relaxation time of AFM spin are usually reported in second timescale (∼ 10 2 − 10 4 s) [4][5][6]. In contrast, at shorter measurement timescales the relaxation time of exchange bias system was demonstrated to cover a wide range ( ∼ 10 −8 − 10 11 s) [15][16][17][18], which has been ascribed to the magnetization reversal mechanism of FM layer [14]. Hence, the report only on AFM spin dynamic behaviour in the millisecond timescale is still sparse.…”