Micromagnetism and magnetization reversal of embedded ferromagnetic elements

Abstract

A unique type of ferromagnetic microelement is explored. Unlike conventional ferromagnetic elements, the entities studied here are not separated topographically from each other, but embedded into a surrounding, continuous film. Fabrication of such elements is achieved by local irradiation of antiferromagnetically coupled $\mathrm{Fe}∕\mathrm{Cr}∕\mathrm{Fe}$ trilayers with $30\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ ${\mathrm{Ga}}^{+}$ ions, which cause a local destruction of the Cr interlayer in these systems. As a result, a transition to ferromagnetic properties is induced within micron-sized irradiated areas, which act as ferromagnetic elements. Since the surrounding area of these elements consists of magnetic material, i.e., two Fe layers which are still antiferromagnetically coupled, interesting coupling phenomena in lateral direction can be observed. In particular, the magnetic configuration within such systems leads to the formation of complex domain walls at the boundary between irradiated and nonirradiated areas exhibiting different types of fine structure. In addition, it is found that the capability of storing information in the form of magnetic single domain states in remanence depends on the geometry of the patterned elements. The fabrication method presented here is an efficient way to create magnetic model systems on the micron scale of different geometries and sizes for comparative studies of micromagnetics and magnetization reversal processes.