  Raman studies on Ca4Al2O5.7Fe2As2 superconductor in the temperature range of
5 K to 300 K, covering the superconducting transition temperature Tc ~ 28.3 K,
reveal that the Raman mode at ~ 230 cm-1 shows a sharp jump in frequency by ~ 2
% and linewidth increases by ~ 175 % at To ~ 60 K. Below To, anomalous
softening of the mode frequency and a large decrease by ~ 10 cm-1 in the
linewidth is observed. These precursor effects at T0 (~ 2Tc) are attributed to
significant superconducting fluctuations, possibly enhanced due to reduced
dimensionality arising from weaked coupling between the well separated (~ 15
{\AA}) Fe-As layers in the unit cell. A large blue-shift of the mode frequency
between 300 K to 60 K (~7%) indicates strong spin-phonon coupling in this
superconductor.
