Positive isotropic resonance field shift of exchange coupled wedged-permalloy/FeMn bilayers.

Exchange-coupled wedged-permalloy/uniform-FeMn bilayers are studied by ferromagnetic resonance and magnetometry measurements with applied field parallel to the film plane. An additional weak resonance peak was observed besides an intense resonance, indicating the existence of interfacial diffusion. For all samples, the exchange field measured by the ferromagnetic resonance is close to that by magnetometry measurements. For the wedged-Py/FeMn bilayers, the in-plane isotropic resonance field shift is positive and inversely proportional to the ferromagnetic layer thickness. It is originated from either specific geometry of Py layer thickness or interfacial diffusion. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]