Passage: In 1986 he discovered the antiparallel exchange coupling between ferromagnetic layers separated by a thin non-ferromagnetic layer, and in 1988 he discovered the giant magnetoresistive effect (GMR). GMR was simultaneously and independently discovered by Albert Fert from the Université de Paris Sud. It has been used extensively in read heads of modern hard drives. Another application of the GMR effect is non-volatile, magnetic random access memory.

Question: What year did he discover the GMR?
1988