Magnetization dynamics of weak stripe domains in Fe–N thin films: a multi-technique complementary approach

Abstract

The resonant eigenmodes of a nitrogen-implanted iron α'-FeN characterized by weak stripe domains are investigated by Brillouin light scattering and broadband ferromagnetic resonance experiments, assisted by micromagnetic simulations. The spectrum of the dynamic eigenmodes in the presence of the weak stripes is very rich and two different families of modes can be selectively detected using different techniques or different experimental configurations. Attention is paid to the evolution of the mode frequencies and spatial profiles under the application of an external magnetic field, of variable intensity, in the direction parallel or transverse to the stripes. The different evolution of the modes with the external magnetic field is accompanied by a distinctive spatial localization in specific regions, such as the closure domains at the surface of the stripes and the bulk domains localized in the inner part of the stripes. The complementarity of BLS and FMR techniques, based on different selection rules, is found to be a fruitful tool for the study of the wealth of localized mag-netic excitations generally found in nanostructures.

Straight motion of half-integer topological defects in thin Fe-N magnetic films with stripe domains

“…Note, however, that in the case of our Fe-N film there is no physical patterning: rather, the field-induced displacement of magnetic edge dislocations along straight tracks is related to the very existence of a well-defined magnetic stripe domain pattern. To this regard, another interesting property of Fe-N films 22 , 46 is worth mentioning: an almost rigid stripe pattern rotation can be achieved simply by saturating the magnetization along a given in-plane direction, and subsequently removing the field. As a consequence of this “rotatable anisotropy” 47 – 51 , the axis of propagation of the topological defects can be rotated in the same way.…”

Control of domain structure and magnetization reversal in thick Co/Pt multilayers

“…In these systems, magnetocrystalline and surface anisotropies are typically opposing the magnetostatic selfinteraction, causing the occurrence of heterogeneous microscopic magnetic states in order to minimize their total energy [17,[19][20][21]. The resulting nanoscale magnetic textures have attracted significant interest due to their technological potential [22][23][24][25][26][27][28], as well as for their structural complexity [29][30][31][32]. In particular magnetic bubbles, which correspond to cylindrically shaped domains extending throughout the total thickness [33], were intensively studied largely motivated by their potential for applications in solid state storage [34,35].…”

Stripe domains reorientation in ferromagnetic films with perpendicular magnetic anisotropy

“…Weak stripe domains were first predicted theoretically [32,33] and later discovered experimentally in NiFe films [19,34]. In the following years, the phenomenon has been found and deepened in different kinds of thin films with moderate PMA, such as FeGa [35][36][37][38], FeN [31,39,40], FeSiB [41,42], CoFeB [43], FeTaN [44], GdFe [45], NdCo [46], FeCoZr [23], La x Sr 1−x MnO 3 [47] and multilayers with moderate perpendicular anisotropy [48][49][50]. Very recently, it has been shown [51] that the formation of stripe domains can be induced in a Py film, even far below the critical thickness, by coupling the Py film to a NdCo one, characterized by a moderate PMA.…”