Structure and electrical resistivity of La 1− xBa xMnO 3 (0.25 ≤ x ≤ 0.35) perovskites

Abstract

The structural properties and resistivity of La 1− x Ba x MnO 3 (0.25 ≤ x ≤ 0.35) manganites have been investigated. The Rietveld refinement of X-ray powder diffraction patterns fitted using the FullProf refinement program shows that these compounds having a cubic, and hexagonal structure with space group P m3 m , and R 3 ¯ c for La 1− x Ba x MnO 3 (0.25 ≤ x ≤ 0.35). The temperature dependent resistivity curves undergo a metal–semiconductor transition ( T MS) at ∼200 K ( x = 0.25), ∼220 K ( x = 0.30) and ∼230 K ( x = 0.35) for La 1− x Ba x MnO 3. The temperature dependence of resistivity shows a minimum behavior at low temperatures ( T ≤ 50 K), explained by electron–electron and Kondo-like spin dependent scattering. The metallic resistivity is analyzed, to our knowledge, for the first time highlighting the importance of electron–phonon, electron–electron, and electron–spin fluctuation interactions. For T > T MI the semiconducting nature is discussed with small polaron conduction model.