The invention relates to a method of manufacturing a spin valve structure (1) of the GMR-type. Such a structure includes a stack of a magnetic layer (11a 11b), a nonmagnetic layer (15) and a sense layer (17) of a ferromagnetic material. In order to obtain a spin valve structure having a very good GMR effect the method comprises the following specific steps: oxidation of the ferromagnetic material of the sense layer; deposition of aluminium on the oxidized ferromagnetic material; oxidation of the deposited aluminium using oxygen from the oxidized ferromagnetic material.