  In this work we introduce a new method of a ferromagnetic resonance (FMR)
detection from thin, nm-size, films. Our setup is based on the commercial
piezo-cantilever, used for atomic force microscopy. It has an option to rotate
the sample in the magnetic field and it operates up to the high microwave
frequencies of 160 GHz. Using our cantilever based FMR spectrometer we have
investigated a set of samples, namely quasi-bulk and 84 nm film
Co$_2$FeAl$_{0.5}$Si$_{0.5}$ samples, 16 nm Fe$_{50}$Ni$_{50}$ film and 150 nm
Sr$_2$FeMoO$_6$ film. The high frequency ferromagnetic resonance (FMR) response
from an extremely thin Fe$_{50}$Ni$_{50}$ film we have fitted with the
conventional model for the magnetization dynamics. The cantilever detected FMR
experiments on Sr$_2$FeMoO$_6$ film reveal an inability of the conventional
model to fit frequency and angular dependences with the same set of parameters,
which suggests that one has to take into account much more complicated nature
of the magnetization precession in the Sr$_2$FeMoO$_6$ at low temperatures and
high frequencies. Moreover, the complicated dynamics of the magnetization
apparent in all investigated samples is suggested by a drastic increase of the
linewidths with increasing microwave frequency, and by an emergence of the
second line with an opposite angular dependence.
