Critical current density of MgB2 thin film with pinning centres introduced by deposition in oxygen atmosphere
Critical current density of MgB2 thin film with pinning centres introduced by deposition in oxygen atmosphere
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DOI：
10.1088/0953-2048/18/11/008
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发表时间：
2005-09
影响因子：
3.6
通讯作者：
M. Haruta;T. Fujiyoshi;T. Sueyoshi;K. Miyahara;T. Doi;H. Kitaguchi;S. Awaji;K. Watanabe
中科院分区：
文献类型：
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作者：
M. Haruta;T. Fujiyoshi;T. Sueyoshi;K. Miyahara;T. Doi;H. Kitaguchi;S. Awaji;K. Watanabe
测定了MgB2薄膜的临界电流密度Jc；它们是用电子束蒸发法制备的，没有任何后退火。为了改善Jc在强磁场中的特性，在O2气氛下沉积了MgB2薄膜。在垂直和平行于c轴的磁场中，o2掺杂膜的Jc值超过了未掺杂膜的Jc值。在Jc的角依赖性中观察到由c轴相关钉钉中心引起的Jc峰值。根据垂直于c轴和平行于c轴的两个方向的电阻率曲线的温度依赖性，估计了上部临界场Bc2和涡旋玻璃-液体过渡场Bg。结果表明，在施加磁场的两个方向上，O2的引入均使Bc2和Bg增加。这一事实表明，通过在O2气氛中沉积MgB2薄膜，引入了有效的钉住中心。
Critical current densities Jc of MgB2 thin films have been measured; these were prepared by an electron beam evaporation method without any post-annealing. In order to improve the characteristics of Jc in high magnetic fields, a MgB2 thin film was deposited in an O2 atmosphere. The values of Jc of the O2-doped film have exceeded those of the non-doped film in magnetic fields applied perpendicular and also parallel to the c-axis. The peak of Jc caused by the c-axis correlated pinning centres has been observed in the angular dependence of Jc. The upper critical field Bc2 and the vortex glass–liquid transition field Bg have been estimated from temperature dependences of resistivity curves in both directions of the magnetic fields perpendicular and parallel to the c-axis. It is found that Bc2 and Bg are increased by the introduction of O2 in both the directions of the applied field. This fact indicates that effective pinning centres have been introduced by the deposition of the MgB2 thin film in an O2 atmosphere.