GMR was discovered in layers iron , chrome and ferrite by Peter GrÃ 1\/4 nbergs research team of the JÃ 1\/4 lich Research Centre ( Germany ) in 1988 . Peter GrÃ 1\/4 nberg owns a patent for the technology . GMR was first discovered in 1988 , in Fe\/Cr\/Fe trilayers by a research team led by Peter GrÃ 1\/4 nberg of Forschungszentrum JÃ 1\/4 lich ( DE ) , who owns the patent .