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

Abstract

We report here high-pressure-induced phase transitions observed in nanocrystalline perovskite La 0.8 Sr 0.2 Mn 0.8 Fe 0.19 57 Fe 0.01 O 3 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 ∼140Å. 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 MnO 6 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.

Manganese-based A-site high-entropy perovskite oxide for solar thermochemical hydrogen production

“…The peak around 620 cm −1 can be assigned to the B 2g mode, representing the in-phase stretching of LPNGSB_Mn. 76–79…”

“…The peak around 620 cm −1 can be assigned to the B 2g mode, representing the inphase stretching of LPNGSB_Mn. [76][77][78][79] The structural stability of LPNGSB_Mn was further demonstrated based on the result of Raman. 77 Additionally, the red- shi is observed in the Raman spectra of 50-cycled LPNGSB_Mn indicating the increasing defects in the material structure.…”

Local Electronic Structure Of Heavy-ion Irradiated Nano-crystalline Stoichiometric La0.8Sr0.2Mn0.8Fe0.2O3 Particles Using Highresolution Mössbauer Spectroscopy

“…A cooperative Jahn-Teller distortion and the external pressure together drives the antiferromagnetically coupled eg to align along (001) planes giving rise to ferromagnetic ordering. Laser Raman spectroscopy also supported the conclusion at 0.52 GPa by complete vanishing of the mode representing Fe and by phonon softening of the mode indicating structural instabilities in MnO4 octahedra [16][17][18][19]. 57 Fe Mössbauer spectroscopy is an effective experimental tool to extract information about local electronic structure, symmetry and magnetic ordering surrounding Fe nucleus through its parameters: Isomer shift (IS), Quadrupole splitting (QS) and magnetic hyperfine field (HF).…”

Recent advances in linear and non‐linear Raman spectroscopy. Part III

“…Highpressure-induced phase transitions were observed by Dilawar et al [238] in the nanocrystalline perovskite (LaSr)(MnFe)O 3 by Raman spectroscopy. While the latter gives an overall picture of the vibrations due to all the atoms present, accompanying high-pressure Mössbauer spectroscopy provides information about the environment surrounding the iron atom.…”