Coupled Walls in Multilayer Films

Abstract

If the thickness of an intermediate nonmagnetic layer separating two ferromagnetic layers is larger than the ferromagnetic wall thickness (order of 1 μ), only a magnetostatic interaction at the film edges exists. If the intermediate-film thickness is smaller than the wall thickness, the magnetostatic interaction of the domain walls is essential, yielding special multilayer wall configurations. If the intermediate film is thinner than that necessary for a complete exchange isolation (order of 10 nm), the wall configurations are modified by an exchange coupling between the local magnetizations of the layers. The wall configurations and their influence on the wall motion and switching behavior are reviewed in this paper.

Structure and magnetic properties of FeNi/Ti sputtered multilayers

“…It is logical to suppose that the domain walls situated in different magnetic layers form magnetic structures with a closed or partially closed magnetic flux. Such a structure formation can be associated with a decrease of the energy density corresponding to the domain wall and as a consequence results in a decrease of the coercivity [3,12].…”

“…In multilayeres, strong magnetostatic interactions between the domain walls situated in different magnetic layers are possible. In this case, domain boundaries may form paired domain wall structures with a partially closed magnetic flux and reduced energy, causing, as a consequence, a reduction of the coercivity of the multilayers [3]. Non-magnetic spacer introduction changes the thickness of magnetic layers and as a consequence can affect the crystalline structure of the layers because such parameters as the average grain size, depend on the layer thickness [4].…”

Electron microscopy of the magnetic structure of thin films

“…В пленках Со -А1 полосовые домены наблюдались при толщинах 350-700 А. Пленки с полосовыми доменами имели харак-терную петлю гистерезиса, и для их насыщения было нужно поле в 500 э. Эти пленки имели только о. ц. к. структуру 376 . В многослойных пленках за счет взаимодействия магнитных слоев возникает специфическая доменная структура 302 . 23,46,31,41,[313][314][315] 2.…”

Magnetic coupling in composite ferromagnetic film structures

“…Clow (20) observed that coercive force of laminated Ni-Fe films are greatly reduced because of the wall inter action. Domain wall structures under the influence of the interaction have been studied theoretically by many workers (5,6,(21)(22)(23)(24)(25)(26) and experimentally by others (7,19,27,28 In general, the exchange coupling can be divided into positive coupling and negative coupling in the sense that, as the result of the coupling, the magnetizations in the two layer tend to orientate parallel or antiparallel, respectively. Whereas the positive exchange coupling can be observed in a composite film structure of two ferromagnetic films either in intimate contact (10,(33)(34)(35)(36) or with thin separation (9, 37-39), the negative exchange coupling can only be found between a ferromagnetic film and an antiferromagnetic film in intimate contact (40,41) …”

“…This interest is stimulated partly from the fact that coupled film structures provides an effective way of improving magnetic film properties with respect to computer memory applications (3)(4)(5)(6)(7)(8)(9)(10), and partly from the potential application of localized domain wall interactions in composite film structures as large-capacity files (11). In general, the magnetic coupling observed in multilayer film structures with two or more magnetic films either in intimate contact or in sufficient proximity can be classified by its nature into two groups, namely the magnetostatic coupling and the exchange coupling.…”