| Investigation the positive moments on the M－T curve of YBCO films measured by using zero-field cooling |
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| 引用本文： | 郭树权,王凤林,周岳亮,赵柏儒,高炬. Investigation the positive moments on the M－T curve of YBCO films measured by using zero-field cooling[J]. 中国物理, 2002, 11(4): 379-382 |
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| 作者姓名： | 郭树权 王凤林 周岳亮 赵柏儒 高炬 |
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| 作者单位： | Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084, China; National Laboratory for Superconductivity, Institute of Physics, Chinese Academy Science, Beijing 100080, China; Department of Physics, The Unive;Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084, China;National Laboratory for Superconductivity, Institute of Physics, Chinese Academy Science, Beijing 100080, China;National Laboratory for Superconductivity, Institute of Physics, Chinese Academy Science, Beijing 100080, China;Department of Physics, The University of Hong Kong, Hong Kong, China |
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| 基金项目： | Project supported by the National High Technology Development Programme of China (Grant No 863-CD090000). |
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| 摘 要： | The superconducting transition of a YBCO film was measured by a MPMS-5 superconducting quantum interference device magnetometer, using a zero-field cooling process. The experimental results have shown that there are positive magnetic moment and positive peak on the M－T curve. We have proven that these anomalous behaviours are due to measurement error, but not phase transition. We have proposed a simple formula to explain and to calculate quantitatively these anomalous behaviours. It was found that, provided dH>0.59Hp (dH is the inhomogeneous field of the remnant field, Hp is the fully penetrated field of the measured sample), the experimental results will be positive, not negative. If dH≥2Hp, the experimental results will be symmetrical to their real negative values. From the M－T curve, which has positive moment and positive peak below Tc (superconducting transition temperature), we found a new possible method to obtain Hp of the measured sample.
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| 关 键 词： | SQUID magnetometer remnant field superconducting M－T curve flux pinning positive moment superconducting paramagnetic Meissner effect |
| 收稿时间： | 2001-04-20 |
Investigation the positive moments on the M－T curve of YBCO films measured by using zero-field cooling |
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| Guo Shu-Quan,Wang Feng-Lin,Zhou Yue-Liang,Zhao Bai-Ru and Gao Ju. Investigation the positive moments on the M－T curve of YBCO films measured by using zero-field cooling[J]. Chinese Physics, 2002, 11(4): 379-382 |
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| Authors: | Guo Shu-Quan Wang Feng-Lin Zhou Yue-Liang Zhao Bai-Ru Gao Ju |
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| Abstract: | The superconducting transition of a YBCO film was measured by a MPMS-5 superconducting quantum interference device magnetometer, using a zero-field cooling process. The experimental results have shown that there are positive magnetic moment and positive peak on the M－T curve. We have proven that these anomalous behaviours are due to measurement error, but not phase transition. We have proposed a simple formula to explain and to calculate quantitatively these anomalous behaviours. It was found that, provided dH>0.59Hp (dH is the inhomogeneous field of the remnant field, Hp is the fully penetrated field of the measured sample), the experimental results will be positive, not negative. If dH≥2Hp, the experimental results will be symmetrical to their real negative values. From the M－T curve, which has positive moment and positive peak below Tc (superconducting transition temperature), we found a new possible method to obtain Hp of the measured sample. |
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| Keywords: | SQUID magnetometer remnant field superconducting M－T curve flux pinning positive moment superconducting paramagnetic Meissner effect |
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