Phonon Raman scattering in R{sub 1{minus}x}A{sub x}MnO{sub 3+{delta}} (R=La,Pr; A=Ca,Sr)

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.58.11435· OSTI ID:665566

Granado, E; Moreno, N O; Garcia, A; Sanjurjo, J A; Rettori, C; Torriani, I ^[1]; Oseroff, S B ^[2]; Neumeier, J J; McClellan, K J ^[3]; Cheong, S ^[4]; Tokura, Y ^[5]

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1. Instituto de Fisica Gleb Wataghin, UNICAMP, 13083-970, Campinas-SP (Brazil)
2. San Diego State University, San Diego, California 92182 (United States)
3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
4. ATT Bell Laboratories, Murray Hill, New Jersey 07974 (United States)
5. Department of Physics, University of Tokyo 113 (Japan)

Polarized Raman spectra of single and polycrystalline R{sub 1{minus}x}A{sub x}MnO{sub 3} (R=La,Pr; A=Ca,Sr) ceramic samples were studied as a function of temperature. For the rhombohedral LaMnO{sub 3.1} and La{sub 0.7}Sr{sub 0.3}MnO{sub 3}, the observed Raman peaks were associated with modes arising from the folding of the Brillouin zone under lattice deformation. For the orthorhombic LaMnO{sub 3.0}, the Raman spectra are consistent with the Pnma structure and show an anomalous {ital softening} of the 494 and 604 cm{sup {minus}1} modes below the antiferromagnetic ordering temperature T{sub N}{approx_equal}140 K. Polycrystalline samples of La{sub 0.5}Ca{sub 0.5}MnO{sub 3} show a dramatic change of the Raman spectra between 100 and 160thinspK, which was associated with the increase of the orthorhombic distortion observed by others for T{approx_lt}240 K. Other R{sub 1{minus}x}A{sub x}MnO{sub 3} single crystals, with small orthorhombic distortions, show Raman spectra which are similar to those observed in the rhombohedral samples. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 665566
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 17 Vol. 58; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETIC MATERIALS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CRYSTAL STRUCTURE
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MANGANESE OXIDES
NEEL TEMPERATURE
ORTHORHOMBIC LATTICES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RAMAN SPECTRA
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TEMPERATURE RANGE 0065-0273 K