Journal of Applied Physics · 2004 · 13 citations · 15 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsMagnetic MaterialsMaterials CharacterizationMagnetic CharacterizationMagnetic OxidesMagnetic Properties Of SolidsMagnetism In SolidsMagnetism Of Inorganic CompoundsX-ray CrystallographyGrain BoundariesGrain Size Effects On MagnetizationMagnetic Materials CharacterizationMagnetic PropertiesMagnetic Property CharacterizationMagnetoresistanceMetal-insulator TransitionPhysical Properties
Polycrystalline La0.7Ca0.3MnO3−δ (LCMO), prepared by a solid-state reaction, was annealed at different temperatures TA. The variation of TA was responsible for observed changes in the physical properties, including a shift in the metal-insulator transition temperature, which is explained by variation in the oxygen content. At low temperatures the magnetization of LCMO samples was also observed to be dependent on TA. A reduction of the grain boundaries leads to enhancement of both the magnetization and the sensitivity for low-field magnetoresistance. By using Mn L3-edge x-ray absorption, it was also found that the Mn3+∕Mn4+ ratio increases with the grain size, and that the oxygen content in LCMO is governed by the grain boundaries.
15
Thousandfold Change in Resistivity in Magnetoresistive La-Ca-Mn-O Films
S. Jin, T. H. Tiefel, M. McCormack et al. · Science · 1994 · 4.8K citations
Natural Sciences, Materials Engineering, Materials Science +17