Magnetic normal modes of bicomponent permalloy/cobalt structures in the parallel and antiparallel ground state

Abstract

Two-dimensional arrays of bicomponent structures made of cobalt and permalloy elliptical dots with thickness\ud of 25 nm, length 1 μm, and width of 225 nm, have been prepared by a self-aligned shadow deposition technique.\ud Brillouin light scattering has been exploited to study the frequency dependence of thermally excited magnetic\ud eigenmodes on the intensity of the external magnetic field, applied along the easy axis of the elements. Several\ud modes have been observed while sweeping the field along the major and minor hysteresis loops, encompassing\ud both the parallel and the antiparallel alignment of the magnetization in adjacent permalloy and cobalt dots.\ud Micromagnetic simulations based on the dynamic matrix method enabled us to successfully reproduce the\ud measured evolution of the frequencies with the field, as well as to identify the spatial profiles of the modes.\ud A marked difference in the field dependence of the frequency of some modes has been observed for parallel\ud and antiparallel magnetization configurations, suggesting the possibility of tuning the dynamic response in a\ud reprogrammable way. The role of both static and dynamic magnetic coupling in determining the mode frequency\ud is discussed in detail by studying the frequency evolution as a function of the gap size between the dots

Evolution of the structural and magnetic properties of sputtered TbxFe73Ga27-x (7 at.% ≤ x ≤ 11 at.%) thin films upon the increase of Tb content

“…3, is 5 nm. This value is much lower than the lift height (80 nm) used in the MFM measurements, confirming the uncorrelation between the two signals [31,32]. The results shown in Fig.…”

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

“…The in-plane magnetic field has been applied along the [−1, 1, 0] crystallographic direction. MFM measurements were performed without removing the sample from the magnetic field region, in order to analyze the changes in the domain structure of a specific area, caused by variations of the field intensity 54 , 55 . During the MFM measurements we observed negligible drift effects, carefully monitored by AFM and in case compensated by small displacements of the scanned area, in order to be sure of exploring the same region of the sample at every field.…”

Rotation of stripe domains in a sputter deposited Tb-Fe-Ga thin film

“…We measured in-plane hysteresis loops by VSM at different angles between the in-plane reference direction (the long side of the sample) and the in-plane applied magnetic field. In-field Magnetic Force Microscopy (MFM) measurements, at 50 nm lift scan height, were performed without removing the sample from the magnetic field region, in order to analyze the changes in the domain structure of a specific area, caused by intensity field variations, using a technique and instrumentation described in references [18,19,20]. During the MFM measurements we observed negligible drift effects, carefully monitored by AFM and consequently compensated by small displacements of the scanned area, in order to be sure of exploring the same area at every field.…”