Infra-red Spectroscopic Studies of GdBaCo2O5.5

This paper reports infrared spectroscopic studies on GdBaCo${}_2$O${}_{5.5}$ layered perovskite which exhibits successive magnetic transitions from paramagnetic to ferromagnetic to antiferromagnetic states as well as high temperature metal to insulator transition and a change in charge transport mechanism at low temperature. Infrared absorption spectra recorded at various temperatures in the range 80 K to 350 K reveal changes in the positions of Co-O stretching and bending frequencies which provide an explanation to the magnetic and transport behaviour of this compound.