  Coronal loops exist ubiquitously in the solar atmosphere. These loops puzzle
astronomers over half a century. Solar magneto-seismology (SMS) provides a
unique way to constrain the physical parameters of coronal loops. Here, we
study the evolution of oscillations of a coronal loop observed by the
Atmospheric Imaging Assembly (AIA). We measure geometric and physical
parameters of the loop oscillations. In particular, we find that the mean
period of the oscillations increased from 1048 to 1264 s during three
oscillatory cycles. We employ the differential emission measure method and
apply the tools of SMS. The evolution of densities inside and outside the loop
is analyzed. We found that an increase of density inside the loop and decrease
of the magnetic field strength along the loop are the main reasons for the
increase in the period during the oscillations. Besides, we also found that the
amplitude profile of the loop is different from a profile would it be a
homogeneous loop. It is proposed that the distribution of magnetic strength
along the loop rather than density stratification is responsible for this
deviation. The variation in period and distribution of amplitude provide, in
terms of SMS, a new and unprecedented insight into coronal loop diagnostics.
