Infrared spectroscopic studies of

This paper reports infrared spectroscopic studies on GdBaCo2O5.5 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 80–350 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.