Thickness and annealing temperature dependences of magnetization reversal and domain structures in exchange biased Co/Ir–Mn bilayers

Domain structure and magnetization reversal process of exchange-coupled ferromagnet/antiferromagnet bilayers Co(x)/Ir–Mn(10 nm) were studied as a function of both thickness of the Co layer and annealing temperature. The exchange bias field of the thinnest film and the coercive field of the thicker films show monotonic increase at annealing temperature above 250 °C. In every case the bilayers are remagnetized by domain nucleation and domain wall motion. Domain size decreases rapidly for high annealing temperatures, while x-ray diffraction study indicated that the crystallographic texture did not change significantly. The observed features are discussed taking into account the magnetic structure at the interface and its evolution during annealing.