Change of RF susceptibility and parametric oscillations of the magnetization of stripe films in magnetic fields normal to the surface

Multidomain ferromagnetic resonance (FMR) for Permalloy magnetic fills (thickness 2700 Å) 83 percent Ni with rotatable anisotropy was experimentally observed with an external magnetic field applied normal to the sample surface. The lower frequency branch of multidomain FMR was excited when the RF magnetic field
h
was oriented along the film plane; for
h
oriented parallel to the field
H_{\perp}
the higher frequency branch was excited. The dependence of the resonant field
H_{\perp}
on the frequency of field
h
for multidomain and single-domain FMR was determined. Increasing the RF field
h
oriented along
H_{\perp}
gave rise to oscillations of magnetization with the frequency
(1/2)f
, where
f
is the pumping frequency. The dependence of the amplitude of these oscillations on the strength of the RF field
h
and on the magnetizing field
H_{\perp}
was investigated.