Measurements of the mobility of domain walls in permalloy films in a wide thickness range

10.1007/s11451-008-2001-4

“…Even for h/Λ < 11, the twisting is so weak that HBLs cannot arise in the DW and the limiting steady-state velocity is close to the Walker velocity [46]. In [238], the limiting velocity of a quasi-Bloch wall in a film with h < Λ was found to be (63) and it was assumed that, at a thickness h ~ Λ, the limiting velocity reaches a maximum, because this velocity is proportional to 1/h in films with h ӷ Λ. The same conclusions concerning the structure and velocity of the DW were drawn in [239,240].…”

“…A wealth of data has been obtained on DW dynamics in permalloy films with an easy axis lying in the film plane [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76]. The parameter values of such films (consisting of approximately 80 wt % Ni and 20 wt % Fe) are as follows: A = 10 -6 erg/cm, K = 10 3 erg/cm 3 , M = 800 G, and the thickness is approximately 150 Å to a few micrometers.…”

“…The mobilities µ r and µ s differ in terms of their dependence on h. Therefore, by analyzing the µ(h) dependence, one can determine the factors that restrict the DW velocity [58,61,63,65,67,68,73,74]. Figure 6 shows the data from [63], where the relation between V and H was studied in detail for films of various thicknesses. In very thin films (150 < h < 400 Å), the V(H) dependence is linear and the DW mobility decreases as h increases.…”

“…Dependence of the DW mobility µ on the film thickness plotted on a semilogarithmic scale (data from[63]): (I) µ 1 , (II) µ 2 , and (III) µ 3 for a cylindrical film 1 µm thick. Curves 1 and 2 are calculated for the cases where the energy loss is associated with spin precession damping and eddy currents, respectively.…”