Eur. Phys. J. B 44, 557-562 (2005)
https://doi.org/10.1140/epjb/e2005-00156-9

Isotropic ferromagnetic resonance field shift in as-prepared permalloy/FeMn bilayers

¹ Surface Physics Laboratory (State Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433, China
² Department of Physics, Shanghai University, Shanghai 200444, China
³ Center for Material Analysis and Measurements, Nanjing University, Nanjing 210093, China

Corresponding author: ^a shimingzhou@yahoo.com

Received: 14 September 2004
Revised: 2 January 2005
Published online: 30 May 2005

Abstract

Exchange-coupled wedged-permalloy (Py)/FeMn bilayers are studied by ferromagnetic resonance (FMR) technique at room temperature. In comparison, Py single layer films were also made. For Py single layer films and Py/FeMn bilayers, only one uniform resonance peak was observed at high magnetic fields, indicating no interfacial diffusion at the Py/FeMn and Py/Cu interfaces. Negative isotropic in-plane resonance field does exist in Py/FeMn bilayers and its magnitude increases with decreasing Py layer thickness. In order to explain above phenomena, interfacial perpendicular anisotropy must be considered simultaneously, in addition to irreversible rotation of spins in FeMn layers. This is because the perpendicular resonance field of the bilayers is larger than that of Py single layer films.