Electrical and magnetic properties of strontium substituted lanthanum manganate perovskite crystals prepared using fused salt electrolysis
- Rider Univ., Lawrenceville, NJ (United States). Chemistry Dept.
- Rowan Univ., Glassboro, NJ (United States). Dept. of Chemistry and Physics
- Rutgers-the State Univ., Piscataway, NJ (United States). Dept. of Chemistry
Crystals of Sr-doped perovskite lanthanum manganates, containing 7--34 mole percent Sr have been grown by fused salt electrolysis using Cs{sub 2}-MoO{sub 4}-MoO{sub 3} solvents in stabilized zirconia crucibles. The rhombohedral crystals grow with cubic-like habits typically with facial areas 0.25--4 mm{sup 2} on edge with the average facial area decreasing with increasing Sr content. All measured crystals with Sr contents between 11.7 and 33.6 mole percent SR underwent transitions from a paramagnetic-insulator to a ferromagnetic-metallic state with values of {Tc} and T{sub IM} between 325 and > 400 K (for T{sub IM}), the values increasing with Sr content. A magnetoresistance of approximately 45% at 375 K was observed for a crystal of composition Sr{sub 0.336}La{sub 0.661}Mn{sub 0.997}O{sub 3}. The anomalously high {Tc} = 325 K for Sr{sub 0.117}La{sub 0.844}Mn{sub 0.990}O{sub 3} for a sample of such low Sr content is interpreted in terms of a high vacancy level on the A cation site which stabilizes the rhombohedral perovskite structure, which otherwise might have been expected to be orthorhombic type-1. The formation of Sr-doped lanthanum manganate perovskite at the cathode with the orthorhombic type-2 structure is interpreted in terms of an electrostatically assisted air oxidation mechanism. 42 refs., 4 figs., 2 tabs.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 679222
- Journal Information:
- Journal of Solid State Chemistry, Vol. 145, Issue 1; Other Information: PBD: Jun 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transport properties and magnetic behavior in the polycrystalline lanthanum-deficient manganate perovskites ({approx}La{sub 1{minus}x}MnO{sub 3})
Structural characterization of the perovskite series Sr{sub 1−x}La{sub x}Ti{sub 0.5}Mn{sub 0.5}O{sub 3}