Exchange-bias-like effect in Ll₀ (111) FePt based pseudo spin valves

The coupling between hard FePt/CoFe and soft CoFe/NiFe layers through a Cu spacer has been studied in L1₀ (111) FePt(20)/CoFe(1.5)/Cu(3.5 or 4.5)/CoFe(2)/NiFe(3) (in nm) pseudo spin valves. The soft layer hysteresis loops exhibit clear shifts in the field axis (exchange bias-like) and a marked coercivity enhancement. The thickness of the Cu layer or the interface roughness influence the exchange bias properties of the systems. This interlayer coupling arises from the competition between dipolar and RKKY interactions between the layers.