PUB - Publikationen an der Universität Bielefeld

Since the late 1980's there has been an enormous research on stacks of thin layers of ferro- and paramagnetic metals triggered by the discoveries of interlayer coupling and its oscillatory behavior regarding the spacer layer thickness. The discovery of the giant magnetoresistance (GMR) effect and all related effects underlined the high application potential of these new multilayer systems. All this came along with improved deposition, especially sputtering devices, and investigation methods capable of producing, controling and examining thin films of only a few nanometers. Although GMR multilayers have already found their way into automotive sensor technology and into leading-edge hard disk drive products there are still many unsolved questions on both ends of the technological span. This thesis successfully addresses on one hand the basic understanding of the oscillatory behavior in one of the simplest stacking sequences combining interlayer exchange coupling and exchange bias, the interlayer coupled and pinned magnetic trilayer. Here the results definitely respond to the question about the existence of a lower limit of about 2 nm below which no antiferromagnetic alignment can be realized in spin valve structures. On the other hand the transfer of laboratory results to a MST production line is investigated, especially the cost saving realization of a Wheatstone bridge. A special feature of this thesis is the introduction of a new simulation tool for GMR characteristics. Its applicability to understand experimental results was demonstrated as well as its capability to predict characteristics of newly designed stacking sequences and other application related questions.