A permanent magnet includes a stack of N patterns stacked immediately one above the other in a stacking direction, each pattern including an antiferromagnetic layer made of antiferromagnetic material, a ferromagnetic layer made of ferromagnetic material, the directions of magnetization of the various ferromagnetic layers of all the patterns all being identical to one another. At least one ferromagnetic layer includes a first sub-layer made of CoFeB whose thickness is greater than 0.05 nm, and a second sub-layer made of a ferromagnetic material different from CoFeB and whose thickness is greater than the thickness of the first sub-layer.