Study of high-pressure-induced phase transition in nanocrystalline perovskite (LaSr)(MnFe)O3by Raman spectroscopy



We report here high-pressure-induced phase transitions observed in nanocrystalline perovskite La0.8Sr0.2Mn0.8Fe0.1957Fe0.01O3 as a function of pressure up to 9.2 GPa at room temperature by Raman spectroscopy. The nanocrystalline sample, synthesized by the sol–gel technique showed crystallite sizes of ∼140 Å. The peaks originated as a consequence of the nano size of the sample as well as the Fe doping, reported for the first time in these manganites, could be identified and seem to be affected strongly by the application of pressure. Phonon softening observed in MnO6 octahedra indicated structural instabilities with pressure and could be correlated to the Mössbauer parameter–quadrupole splitting. The results tally very well with those of high-pressure Mössbauer spectroscopy and electrical resistivity measurements. Copyright © 2008 John Wiley & Sons, Ltd.