Elaboration and Characterization of Materials from the LaMnO 3 –BiMnO 3 Binary System

Mourad Djahmoum (1) , Omar El Kechaï (1) , Pascal Marchet (2)

1 UMMTO - Université Mouloud Mammeri [Tizi Ouzou]
2 SPCTS-AXE3 - Axe 3 : organisation structurale multiéchelle des matériaux

The study of the La(1-x)BixMnO3 system was carried out using X-ray diffraction and electrical measurements. A continuous solid solution was evidenced for the LaMnO3 rich part of this system (x ≤ 0.6). According to the analyses of XRD results, a rhombohedral symmetry (3) was observed for x ≤ 0.4 and a cubic structure for x = 0.5. The structural study allowed to determine an increase of the mean perovskite lattice parameter, together with a decrease of the rhombohedral angle up to a cubic symmetry for x = 0.5. For x > 0.6, the system is no more single-phased. Impedance measurements were carried out for ceramics in a wide frequency range (100 Hz-1 MHz), between room temperature and 800°C. The exponential decrease of the AC conductivities (σAC) and the room temperature values correspond to a semiconducting behavior. DC conductivity measurements (σDC) were also performed below room temperature (25K < T < 300K). The results evidence for a metal-insulator phase transition. For the exponential part of the σDC curves, the gap energy is between 0.1 and 0.2 eV, confirming the semiconductor behavior of these materials.

Mots clés: perovskites; solid solution; phase transitions; semiconductor materials; ceramics

Domaines: Matériaux; Chimie inorganique

Mourad Djahmoum, Omar El Kechaï, Pascal Marchet. Elaboration and Characterization of Materials from the LaMnO 3 –BiMnO 3 Binary System. physica status solidi (a), In press, ⟨10.1002/pssa.201900814⟩. ⟨hal-02465803⟩