"Nowadays, practically all high-capacity information storage is based on hard disk drive (HDD) technology, which utilizes magnetic materials as a recording media on rotating disk platters. Presently, the HDD industry is undergoing a major technology transformation towards perpendicular magnetic recording (PMR), in which the ‘magnetic bits’ are aligned perpendicularly to the disk surface. Many aspects of PMR technology, however, are only poorly understood at the present time. Specifically, there exists a severe lack of accurate characterization methods for recording media. As a consequence, the optimization process to take full advantage of PMR technology is far from being achieved today. The present proposal for an international reintegration grant for Dr. Hovorka (Drexel University, USA) is aimed at developing an accurate characterization technique for PMR media based upon a quantitatively exact analysis of their complex magnetization behavior. The challenge is to understand the physics of partially correlated reversal, which is mediated by the sufficiently strong grain-to-grain interactions. The project will build on realistic microscopic modeling for numerical and analytic method development to derive quantitatively accurate analysis schemes of magnetization reversal as the foundation for reliable characterization methods of PMR media. The main goals of this proposal are: (a) to establish Dr. Hovorka’s reintegration into the European research community while allowing him to reach a high level of professional maturity for the overall benefit of the European knowledge society, (b) to expand Dr. Hovorka´s solid basic research expertise in nano-magnetism by adding technology-oriented competencies at an advanced level, and (c) to allow nanoGUNE, the host institution, to complement its expertise in such a way that it can maintain and even extend its world-wide leadership position in PMR materials characterization."