| The magnetic coupling between different layers of a magnetic multilayer is a key factor in magnetic storage technologies that influences the effective reading and writing of information. Compared to in-plane magnetized devices, high density magnetic random access memory units which employ multilayers with perpendicular magnetic anisotropy (PMA) have numerous advantages. However, such multilayers, with specialized materials and structural complexities, inevitably introduce new magnetic coupling phenomena and mechanisms into the system. It is therefore necessary to study the behavior, temperature dependence and underlying physics of interlayer exchange coupling (IEC) and exchange bias (EB) in the context of PMA multilayers.This thesis centers around PMA multilayers with CoFeB alloy components, and synthetic antiferromagnets (SAFs) and exchange biased stacks based on such multilayers. Due to the interfacial origin of its PMA, the periodic [CoFeB/Pt or Pd] structure differs from in-plane magnetized films in the thickness of individual ferromagnetic layers and the prominence of interface related effects, but the influence of such differences on the characteristics of magnetic coupling are not yet well understood. By using such methods as varying adjacent CoFeB thickness, layer insertion at interfaces, temperature dependent measurement and thermal annealing, this thesis studies in detail the role of interfaces and film thickness in IEC and EB, providing useful information for the fabrication of spintronics devices with PMA.The thesis is divided into three major parts:1. Synthetic antiferromagnetic stacks are prepared with the structure of [Pt/ CoFeB]N1/Ru/[CoFeB/Pt]N2.The influence of various structural and measurement parameters on the interlayer coupling and magnetization reversal are studied systematically. The strength of IEC shows an oscillatory decay behavior with the thickness of Ru spacer. By changing the bilayer repetition numbers N1 and N2, the magnetization reversal sequence and platform width can be adjusted. By analyzing the dependence of magnetic moment and exchange field on the repetition number, the thickness of a magnetically dead layer can be extracted. The interlayer coupling strength and the AF peak position are measured, along with the temperature dependence of the coupling.2. The factors that influence the temperature dependence of IEC between perpendicular magnetic [CofeB/Pd] multilayers are investigated in detail. It is found, by varying the thickness of CoFeB adjacent to the Ru spacer, that the strength of IEC is affected by thermal magnon excitations in ultrathin magnetic layers, and decreases faster with increasing temperature in samples with thinner CoFeB. The coupling between CoFeB layers through Pd also contributes to the temperature dependence of IEC by modifying exchange strength within the ferromagnetic part. The position of the AF coupling peak is found to shift with temperature and adjacent CoFeB thickness, corresponding to the change in effective dead layer thickness at the interface between CoFeB and Ru. The different contributions of the upper, and lower interfaces of Ru can be separated experimentally.3. The Exchange bias and its temperature dependence in perpendicularly magnetized [CoFeB/Pd]N coupled with Mnlr is investigated systematically. In the range of tCFB≦0.7 nm, the exchange bias strength is found to increase with adjacent CoFeB thickness tCFB at all measurement temperatures, while the distribution and peak of the blocking temperature TB also depends on tCFB.The exchange bias fields show different trends with annealing temperature in top and bottom pinned structures. The coercivity and exchange bias field can be tuned by inserting a thin Pd or Cu layer between CoFeB and Mnlr, or by using a seed layer under the multilayer.
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