Exchange biasing in molecular-beam-epitaxy-grown Fe/Fe50Mn50 bilayers

Exchange biasing and coercive field of molecular-beam-epitaxy-grown Fe/Fe50 Mn50 bilayers have been investigated by Surface Magneto-optical Kerr Effect (SMOKE) and ferromagnetic resonance measurements. The results indicate that there is no exchange biasing when the thickness of antiferromagnetic layer is less than 5.5 nm. The exchange biasing appears when the thickness of an tiferromagnetic layer is greater than 5.5 nm,and the maximum value is reach ed when the thickness is about 7 nm. Exchange biasing and coercive field de crease with further increase of the thickness of the antiferrmagnetic layer . The ferromagnetic resonance measurement results show that there exists un idirectional anisotropy. The above results are discussed in the paper.