Comparison of frequency, field, and time domain ferromagnetic resonance methods

Abstract

We present vector network analyzer ferromagnetic resonance measurements of epitaxial Fe films having a thickness of 16 monolayers. Our
objective is to test the reliability of this novel frequency domain
technique with respect to frequency and damping. For this purpose we
compare vector network analyzer ferromagnetic resonance to pulsed
inductive microwave magnetometry, time resolved magnetooptic Kerr
effect (both methods in the time domain), and conventional
ferromagnetic resonance (measured in the field domain) in terms of
position and width of the ferromagnetic resonance. In addition, we
compare the various techniques with respect to the signal to noise
ratio of the raw data. All data is obtained using the same well
characterized ultrathin magnetic Fe/GaAs (0 0 1) film. Finally, we
demonstrate the potential of the vector network analyzer ferromagnetic
resonance technique for the investigation of nano-structured magnetic
elements having nonuniform magnetization configuration. The absorption
spectrum of Permalloy disks with a diameter of 200 nm and a thickness
of 15 nm shows up to eight distinct resonance peaks. The spatial
structure of the corresponding modes was derived from numerical
calculations and reveals that azimuthal modes up to the fifth order
have been observed inductively. (c) 2006 Elsevier B.V. All rights
reserved.