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Injection Efficiency of Spin-Polarized Quasiparticles in Y-Ba-Cu-O Thin Film |
| YANG Ming1;CAO Chun-Hai1;ZHANG Shi-Yuan2;YANG Sen-Zu1;CUI Xu-Gao2;YOU Li-Xing1;JI Zheng-Ming1;KANG Lin1;XU Wei-Wei1 |
| 1Institute of Superconductor Electronics, Department of Electronic Science and Engineering, Nanjing University, Nanjing 210093
2Department of Physics, Nanjing University, Nanjing 210093 |
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| Cite this article: |
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YANG Ming, CAO Chun-Hai, ZHANG Shi-Yuan et al 2003 Chin. Phys. Lett. 20 1848-1851 |
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Abstract The injection efficiency of spin-polarized quasiparticles in a superconducting Y-Ba-Cu-O (YBCO) film is investigated by means of current injection into the Nd0.7Sr0.3MnO3/SrTiO3/YBa2Cu3O7-δ heterostructures. We have successfully prepared six injection junction windows in the YBCO thin film strip, which are all 5 μm wide, but 80 μm, 40 μm, 20 μm, 10 μm, 5 μm, and 2 μm long, respectively. At 16 K, our YBCO thin film strip (80 nm thick) has Jc = 2 x 105A/cm2. Under the spin-polarized injection current of Iinj = 0.5 mA, with the decrease of injection junction length L, injection efficiency η(η ΔJc/ΔJinj; ΔJc: the suppression of critical current density due to finite ΔJinj increases gradually, till L is not more than 20 μm. In that case, η hardly varies with the change of L, reaching up to about 6. We think that these results are related to the spin diffusion length of spin-polarized quasiparticles in the superconducting thin film. In our heterostructures, the YBCO thin film keeps good superconductivity and the injection junction windows are of proper size, therefore, we have obtained relatively high injection efficiency of spin-polarized quasi-particles.
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| Keywords:
74.50.+r
74.80.Dm
74.60.Jg
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Published: 01 October 2003
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