| Original Articles |
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Spin-Polarized Tunnelling Magnetoresistance Effects in La0.833K0.167MnO3/SrTiO3 Polycrystalline Perovskite Manganites |
| WU Jian1,2;ZHANG Shi-Yuan1;HU Xiu-Kun1 |
| 1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093
2Department of Mathematics and Physics, Hohai University, Nanjing 210098 |
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| Cite this article: |
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WU Jian, ZHANG Shi-Yuan, HU Xiu-Kun 2005 Chin. Phys. Lett. 22 1507-1510 |
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Abstract A sample of La0.833K0.167MnO3-SrTiO3(LKMO/STO) is fabricated by the sol-gel method. The microstructure, magnetic and transportation properties have been studied. X-ray diffraction patterns indicate that the structure of LKMO/STO is a homogeneous solid solution phase. The resistivity of LKMO/STO shows the insulator behaviour, which is different from La0.833K0.167MnO3 (LKMO) whose resistivity shows metal--insulator transition with decreasing temperature. The low-field (mLa0.833K0.167MnO3/SrTiO0 H=0.02T) magnetoresistance decreases from 11% to 0.2% with the increasing temperature from 4K to 220K for the LKMO/STO sample. The magnitude of magnetoresistance in a strong field (La0.833K0.167MnO3/SrTiO0H=5.5T) almost increases linearly with decreasing temperature and reaches the maximum of 65% at the low temperature of 4.2K, which is much higher than that of LKMO (40%). The enhanced low-field magnetoresistance effects are quantitatively explained by the spin-polarized tunnelling at grain boundaries.
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| Keywords:
75.47.Gk
75.47.Lx
75.50.Dd
72.20.My
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Published: 01 June 2005
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| PACS: |
75.47.Gk
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(Colossal magnetoresistance)
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75.47.Lx
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(Magnetic oxides)
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75.50.Dd
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(Nonmetallic ferromagnetic materials)
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72.20.My
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(Galvanomagnetic and other magnetotransport effects)
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