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Enhanced spin-dependent tunneling magnetoresistance in magnetite films coated by polystyrene

journal contribution
posted on 06.04.2007, 00:00 by Wendong Wang, Leszek Malkinski, Jinke Tang
Hematite films were deposited by magnetron sputtering. A phase transformation from hematite to magnetite occurred when polystyrene PS coated hematite films were annealed above 200 °C in hydrogen flow. Giant negative magnetoresistance MR was observed with the best MR ratio of over 8% at room temperature and in a field of 5.5 T found in samples annealed at 230 °C. The temperature dependence of the resistivity is characteristic of intergranular tunneling. After the PS layer was removed and the films annealed again at 230 °C in hydrogen flow, the resistivity increased by about one order of magnitude and the MR ratio decreased to 4.3%. These data show that PS coating layer can protect magnetite films from oxidation and enhance interganular spin-dependent tunneling magnetoresistance.

History

ISO

eng

Language

English

Publisher

University of Wyoming. Libraries

Journal title

JOURNAL OF APPLIED PHYSICS

Collection

Faculty Publications - Physics and Astronomy

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Faculty Publications - Physics and Astronomy

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Exports