Exchange Coupled NiFe/NiMn Bilayer Studied by a Vector Network Analyzer Ferromagnetic Resonance

H. Głowińskia, K. Załęskia, J. Spradab and J. Dubowika aInstitute of Molecular Physics, PAS, M. Smoluchowskiego 17, 60-179 Poznań, Poland bDepartment of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

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Using cavity ferromagnetic resonance and vector network analyzer ferromagnetic resonance unidirectional, uniaxial and rotatable anisotropies were determined in permalloy(30 nm)/NiMn(56 nm). Resonance field dependence on in-plane angle clearly shows unidirectional and uniaxial anisotropy. Rotatable anisotropy, which acts as internal magnetic field independent of a direction of external magnetic field, is observed on vector network analyzer ferromagnetic resonance as upward shift of the resonance frequency of Py/NiMn compared to Py film. Even for a small exchange bias field, this shift is significantly large.

DOI: 10.12693/APhysPolA.121.1145 PACS numbers: 75.70.-i, 75.30.Et, 75.30.Gw, 75.70.Cn, 76.50.+g