Vortex pinning properties and microstructure of MgB2 heavily doped with titanium group elements
Vortex pinning properties and microstructure of MgB2 heavily doped with titanium group elements
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DOI：
10.1088/1361-6668/aa91ed
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发表时间：
2017-11
影响因子：
3.6
通讯作者：
Yuhei Takahashi;T. Naito;H. Fujishiro
中科院分区：
文献类型：
--
作者：
Yuhei Takahashi;T. Naito;H. Fujishiro
The doping of titanium group elements (TGE; Ti, Zr, Hf) to MgB2 is known to improve vortex pinning properties. However, the optimal doping level of each TGE is still a controversial issue. In this study, to improve the critical current density, J c , in high magnetic-field by the TGE-doping, we have studied the vortex pinning properties of (Mg 1 − x TGEx)B2 samples with x ranging in the interval 0 < x < 0.5 . The J c of 1.2 kA cm−2 at 20 K in 3 T for the pristine sample was maximized to 2.9 kA cm−2 for the Ti20%-doped sample, 4.9 kA cm−2 for the Zr30%-doped one, and 5.2 kA cm−2 for the Hf30%-doped one under identical temperature and magnetic field. The irreversibility field, μ 0 H irr , of 3.8 T for the pristine sample was also shifted to a higher field of 4.2 T, 4.3 T and 4.6 T by the Ti20%-, Zr30%- and Hf30%-doping, respectively. Microstractural observations suggested that the grain size, shape and distribution of the MgB2 and impurity phases depended strongly on the species of TGE. We discuss the mechanism of the enhanced vortex pinning properties of the TGE-doped MgB2.
