Fractal domain structures in thin amorphous films

Fractal Dimension of Magnetic Domain Walls in CoFe/Pt Multilayers

“…The fractal properties of magnetic domains have been well described in the thermo-activated relaxation model of domain wall propagation [9,11,14]. In this model, the domain evolution occurs via the Barkhausen jumps of the domain walls by overcoming the breakaway energy R with the help of thermal activation.…”

“…Magnetization reversal in ferromagnetic films with perpendicular magnetic anisotropy occurs by several distinct mechanisms − the wall-motion from existing domains and the nucleation of domains at random positions − depending on the film structure and composition as well as the fabrication conditions [4][5][6][7]. To understand these reversal processes with magnetic properties, many theoretical models, such as the random-field Ising model, the random-bond Ising model [8], the thermally activated relaxation model [9][10][11], and so on, have been proposed and tested. In these models, randomness plays a crucial role.…”

“…From a theoretical point of view, the magnetization reversal occurs through randomly distributed defects in amorphous or poly-crystallized materials and, consequently, such nonlinear stochastic effects result in the fractal nature of the magnetic domain patterns [12]. Many studies have examined the fractal properties of the magnetic domains [9][10][11][12][13][14] and domain walls [9,12]. The fractal dimension provides a unique characterization parameter for domain interface formation in accordance with non-uniformity.…”

Direct observation of dendritic domain growth in perpendicular magnetic anisotropy CoFe/Pt multilayers

“…The origin of the three fundamental mechanisms has been extensively studied. The competition between nucleation and domain wall motion is determined by the relative magnitude of demagnetizing energy and domain wall energy, while the origin of dendritic domain growth remains controversial [10][11][12][13]. On one hand, it has been explained by postulating the existence of local structural variation [10] or magnetic inhomogeneities [11].…”

Creation and Observation of Domain Structures with a Special Kerr Microscope

“…To prove the capability for this purpose it is necessary to investigate domain structures and to create domains thermomagnetically [4]. It has been observed that the type of domains in TbFe or TbFeCo alloy fllms depends strongly on the terbium concentration CTb [5,6]. Recently there has been also some research on the domain structures of TbFe multilayers, which seem to be similar to the structures in alloy films [7].…”