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Abstract <p>Polycrystalline samples of lightly doped manganite La<sub>1–<i>x</i></sub>Ca<sub><i>x</i></sub>Mn<sub>0.98</sub>Fe<sub>0.02</sub>O<sub>3+δ</sub> (<i>x</i>&#xa0;=&#xa0;0.05, 0.1, 0.2) were studied by Raman scattering. With increasing calcium content, the optical LO phonon bands, expressed only in samples of stoichiometric composition (δ = 0, rhombic phase), are significantly weakened and broadened. In individual crystallites (~20%) of the sample with <i>x</i> = 0.05, the temperature dependences of the phonon ν ≈ 610 cm<sup>–1</sup>, corresponding to symmetrical stretching of the MnO<sub>6</sub> octahedra, show softening below the magnetic ordering temperature <i>T</i> ≈ 120 K. This indicates a strong coupling of the magnetic and phonon systems, as well as significant heterogeneity of the lightly doped samples.</p>

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Raman Scattering in Lightly Doped Manganites (La,Ca)Mn0.98Fe0.02O3

  • 期刊论文

  • 发表日期：

    2026年2月1日

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  • S. V. Zaitsev,
  • V. D. Sedykh,
  • K. P. Meletov

摘要

Abstract

Polycrystalline samples of lightly doped manganite La1–xCaxMn0.98Fe0.02O3+δ (x = 0.05, 0.1, 0.2) were studied by Raman scattering. With increasing calcium content, the optical LO phonon bands, expressed only in samples of stoichiometric composition (δ = 0, rhombic phase), are significantly weakened and broadened. In individual crystallites (~20%) of the sample with x = 0.05, the temperature dependences of the phonon ν ≈ 610 cm–1, corresponding to symmetrical stretching of the MnO6 octahedra, show softening below the magnetic ordering temperature T ≈ 120 K. This indicates a strong coupling of the magnetic and phonon systems, as well as significant heterogeneity of the lightly doped samples.