Crystal Structure, Magnetic and Electrical Properties of Half-Doped Chromium Manganite La0.5Sr0.5Mn0.5Cr0.5O3.
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| Title: | Crystal Structure, Magnetic and Electrical Properties of Half-Doped Chromium Manganite La |
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| Authors: | Kallel, Nabil1,2 (AUTHOR) kallel_nabil@yahoo.fr, Hazzez, Mohamed1 (AUTHOR), Ihzaz, Nejib1 (AUTHOR) |
| Source: | Journal of Superconductivity & Novel Magnetism. Aug2019, Vol. 32 Issue 8, p2623-2631. 9p. |
| Subjects: | Crystal structure, Magnetic properties, Rietveld refinement, Manganite, Magnetic measurements, Manganese alloys |
| Abstract: | Polycrystalline sample La0.5Sr0.5Mn0.5Cr0.5O3 (LSMCO) was prepared by a conventional solid-state reaction method in the air, and its structure was determined by Rietveld refinement using consistent resolution time-of-flight X-ray diffraction. Different structural models have been used for analysis of X-ray diffraction data recorded at room temperature, but the best fits have been found using a mixture of rhombohedral and an orthorhombic structural phases (42(1)%/57(1)%). The rhombohedral, centro-symmetric space group R 3 ¯ c No. 167 a ≈ 2 a p c ≈ 2 3 a p Z = 6 with octahedral tilting scheme a−a−a− leading to a three identical out-of-phase tilt angle of (Mn/Cr)-O6 octahedron along three perovskite main directions: x, y, and z-axes. The orthorhombic space group Pbnm No. 62 a ≈ b ≈ 2 a p c ≈ 2 a p Z = 4 with octahedral tilting scheme a−a−c+, leads to an anti-phase tilts of the same magnitude about [100] and [010] directions of the elementary specimen cell and in-phase tilt of different magnitude about the [001] direction. At low temperature 10 K, Rietveld refinement of powder diffraction data revealed that the crystal structure of sample is distorted with a single orthorhombic symmetry (space group Pbnm). Magnetic measurements indicate that our investigated sample exhibits an overall anti-ferromagnetic behavior mainly attributed to the frustration induced by both competing AFM Cr3+-O-Cr3+, Mn4+-O-Mn4+ networks, and the mixed one Mn4+-O-Cr3+exchange magnetic interactions. The temperature dependence of the resistivity measured under zero field shows a semi-conducting behavior in the whole temperature range, which probably could be described by the adiabatic small polaron hoping model with relatively high polaron activation energy. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Polycrystalline sample La0.5Sr0.5Mn0.5Cr0.5O3 (LSMCO) was prepared by a conventional solid-state reaction method in the air, and its structure was determined by Rietveld refinement using consistent resolution time-of-flight X-ray diffraction. Different structural models have been used for analysis of X-ray diffraction data recorded at room temperature, but the best fits have been found using a mixture of rhombohedral and an orthorhombic structural phases (42(1)%/57(1)%). The rhombohedral, centro-symmetric space group R 3 ¯ c No. 167 a ≈ 2 a p c ≈ 2 3 a p Z = 6 with octahedral tilting scheme a−a−a− leading to a three identical out-of-phase tilt angle of (Mn/Cr)-O6 octahedron along three perovskite main directions: x, y, and z-axes. The orthorhombic space group Pbnm No. 62 a ≈ b ≈ 2 a p c ≈ 2 a p Z = 4 with octahedral tilting scheme a−a−c+, leads to an anti-phase tilts of the same magnitude about [100] and [010] directions of the elementary specimen cell and in-phase tilt of different magnitude about the [001] direction. At low temperature 10 K, Rietveld refinement of powder diffraction data revealed that the crystal structure of sample is distorted with a single orthorhombic symmetry (space group Pbnm). Magnetic measurements indicate that our investigated sample exhibits an overall anti-ferromagnetic behavior mainly attributed to the frustration induced by both competing AFM Cr3+-O-Cr3+, Mn4+-O-Mn4+ networks, and the mixed one Mn4+-O-Cr3+exchange magnetic interactions. The temperature dependence of the resistivity measured under zero field shows a semi-conducting behavior in the whole temperature range, which probably could be described by the adiabatic small polaron hoping model with relatively high polaron activation energy. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 15571939 |
| DOI: | 10.1007/s10948-019-4997-4 |
