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RWTH Aachen University, located in Aachen, Germany, is where Peter Grünberg served as a professor. His primary research focus was on solid-state physics, particularly the study of magnetic materials and thin films. His notable contributions to the field include the discovery of giant magnetoresistance (GMR) in 1988, a groundbreaking phenomenon that revolutionized data storage technology and earned him the Nobel Prize in Physics in 2007.