Anomalous anisotropy of critical currents in (Sr, K)Fe2As2 tapes
Anomalous anisotropy of critical currents in (Sr, K)Fe2As2 tapes
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DOI：
10.1088/1361-6668/aa56fd
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发表时间：
2017-03
影响因子：
3.6
通讯作者：
S. Awaji;Y. Nakazawa;H. Oguro;Y. Tsuchiya;Kazuo Watanabe;Y. Shimada;He Lin;C. Yao;Xianping Zhan
中科院分区：
文献类型：
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作者：
S. Awaji;Y. Nakazawa;H. Oguro;Y. Tsuchiya;Kazuo Watanabe;Y. Shimada;He Lin;C. Yao;Xianping Zhan
在不同温度、磁场和磁场方向下，测量了ag -鞘层（Sr， K）Fe2As2带的临界电流和不可逆性场。在最后的热处理中，采用管内粉末热压法制备样品带。在热压（Sr， K）Fe2As2带中，与有效质量各向异性相比，Jc中的逆各向异性可以发现。我们发现，Jc的角依赖性宽c轴峰出现在低场区域，并随着场和温度的增加而减小。此外，在4.2 K温度下，Jc各向异性在10 T左右出现交叉，交叉场随温度升高而减小。认为这些不寻常的各向异性Jc行为可能是由大于相干长度的强随机钉住中心引起的。
We measured critical currents and irreversibility fields of Ag-sheath (Sr, K)Fe2As2 tapes at various temperatures, magnetic fields and magnetic field directions. The sample tapes were made by a powder-in-tube with a hot-press process in the final heat treatments. The inverse anisotropy in Jc in comparison with the effective mass anisotropy can be found in the hot-pressed (Sr, K)Fe2As2 tapes. We found that the broad c-axis peak in angular dependence of Jc appears in a low field region and it decreases with increasing field and temperature. In addition, the crossover of Jc anisotropy appears around 10 T at 4.2 K and the crossover field decreases with increasing temperature. It is considered that these unusual anisotropic Jc behaviors may be originated by the strong random pinning center which is larger than the coherence length,