Spin polarized tunneling in the half-metallic ferromagnet La0.7Sr0.3MnO3: experiment and theory

Abstract

The magnetoresistance (MR) in polycrystalline colossal magnetoresistive compounds follows a behavior different from single crystals below the ferromagnetic transition temperature. This difference is usually attributed to spin polarized tunneling at the grain boundaries of the polycrystalline sample. Here we derive a theoretical expression for the contribution of spin polarized tunneling to the magnetoresistance in granular ferromagnetic systems under the mean field approximation. We apply this model to our experimental data on the half metallic ferromagnet La0.7Sr0.3MnO3, and find that the theoretical predictions agree quite well with the observed dependence of the spin polarized MR on the spontaneous magnetization.

14 pages+5 figures (postscript) Communicated to Phys. Rev. B

References in corpus (5)

• Magnetoresistance of the Double-Exchange Model in Infinite Dimension
• Magnetic Transition Temperature of (La,Sr)MnO${}_3$
• Temperature Dependence of the Conductivity in (La,Sr)MnO${}_3$
• A phenomenological model for magnetoresistance in granular polycrystalline colossal magnetoresistive materials: the role of spin polarised tunnelling at the grain boundaries
• The Density of States of hole-doped Manganites: A Scanning Tunneling Microscopy/Spectroscopy study

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