Epitaxially grown Fe/Ag ultrathin films on GaAs and their application to wideband microwave notch filter

Ultrathin ferromagnetic iron/silver films were epitaxially grown on GaAs su bstrates by molecule beam epitaxy. Sample magnetization and magnetic anisot ropy were studied by magneto-optic Kerr effect experiment. The common featu res in the ferromagnetic resonance peak-to-peak linewidth DeltaH(pp) are id entified, with the narrowest linewidth of 23 Oe. Electronically tunable wid eband notch filters utilizing the flip-chip devices have been realized usin g Fe/Ag film GaAs waveguide layer structures. The peak absorption carrier f requency of a propagating microwave has been tuned in a range from 9.6 to 2 1 GHz in a modest magnetic field from 0 to 1650 Oe for single layer structu re. For multilayer structures, peak absorption is intensified with tuned ra nge from 10.7 to 27 GHz. The experimental results are in good agreement wit h the theoretical predictions for the case in which the magnetic field is a pplied along the easy axis of the Fe film. (C) 2001 Elsevier Science B.V. A ll rights reserved.