Perpendicular magnetization anisotropy induced dynamical coherence reduction in stripe domain film

Abstract

We investigated the magnetization dynamics of the 350 nm Permalloy film with in plane domain (IPD), stripe domain (SD), and labyrinth domain (LD) patterns. Experimental and micromagnetic simulation results showed that the change in magnetic domain structure from IPD to LD was due to the increasing perpendicular magnetic anisotropy (PMA) of the film. The magnetization dynamics indicated that the resonant modes of the film strongly depended on the magnetic domain structure. IPD films presented a uniform precession mode. The film with well-regular SD exhibited clear acoustic and optical resonance modes, and the formation of LD suppressed both resonance modes. Finally, the dynamics of magnetization dependent on the domain structure in these films were discussed by using the phenomenological resonance models.

Stripe Domains in Electrodeposited Ni90fe10 Thin Films

“…Considering our results and literature previously published in electrodeposited and sputtered Ni-Fe alloys [17,[27][28][29], we can correlate the existence of stripe domains to the columnar growth. Moreover, our results indicate that in the considered as 'thick' thickness regime, equal or above 800 nm, stripe domains are not affected by a perpendicular magnetic field applied during growth.…”

Magnetization enhanced the multiple magnetic domain-dominated resonance modes in stripe domain films

“…the strengthening of the SD pattern with increasing film thickness [17,22]. The thickness-dependent out-of-plane hysteresis loops (see figure S5) show a decreasing out of plane saturation field with increasing thickness, which also indicates an improved perpendicular anisotropy with the enhancement of SD pattern [30]. This more pronounced stripe phase is confirmed by the MFM image in figure 3.…”

“…This typical feature of SD film is present due to the onset of a weak perpendicular anisotropy in the stripe phase [22]. Such perpendicular anisotropy in the SD originates from the columnar grain structure of film [30]. We note that the 330 nm film is near the transition region between the in-plane domain and the SD.…”

“…For a SD film, once the film magnetization is saturated, the SD pattern will disappear and a single domain is formed. In this situation, all resonance modes of the film merge into one uniform precessional Kittel mode [30,81], whose frequency depends on the in-plane anisotropy field H k and the saturation magnetization M s of the film and can be estimated by the Kittel equation [82]:…”

“…Therefore, the proportions of the four regions in the SD configuration can be changed by tuning the three energies. Many studies have already been performed on the static and high-frequency magnetic properties of SD by changing the thickness [16,17,19,22,27] or perpendicular magnetic anisotropy [18,[30][31][32][33]. However, the observed resonant peaks excited by the microwave for most experimental results [9,12,15,16,18,19,22,28,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] are weak, and the number of resonant peaks is less than four due to weak contributions from the less dominant regions.…”