摘要Temperature dependence of the upper critical magnetic field (Hc2) near Tc of 20K in a BaFe1.9Ni0.1As2 single crystal is determined via magneto-resistance measurements, for the out-plane (H⊥ab) and in-plane (H || ab) directions in magnetic fields of up to 8T. The upper critical fields at zero temperature estimated by the Werthamer-Helfand-Hohenberg (WHH) formula are μ0 Hc2||(0)= 137T and μ0 Hc2⊥(0) = 51T, both exceeding the weak-coupling Pauli paramagnetic limit (μ0Hp=1.84Tc). However, the WHH formula could overestimate the μ0Hc2|| (0) value. The anisotropy of upper critical fields is around 3 in the temperature range close to Tc. The result is very similar to the Co-doped 122 superconductor BaFe2-xCoxAs2, indicating that electron-doped 122 superconductors exhibit similar superconducting properties.
Abstract：Temperature dependence of the upper critical magnetic field (Hc2) near Tc of 20K in a BaFe1.9Ni0.1As2 single crystal is determined via magneto-resistance measurements, for the out-plane (H⊥ab) and in-plane (H || ab) directions in magnetic fields of up to 8T. The upper critical fields at zero temperature estimated by the Werthamer-Helfand-Hohenberg (WHH) formula are μ0 Hc2||(0)= 137T and μ0 Hc2⊥(0) = 51T, both exceeding the weak-coupling Pauli paramagnetic limit (μ0Hp=1.84Tc). However, the WHH formula could overestimate the μ0Hc2|| (0) value. The anisotropy of upper critical fields is around 3 in the temperature range close to Tc. The result is very similar to the Co-doped 122 superconductor BaFe2-xCoxAs2, indicating that electron-doped 122 superconductors exhibit similar superconducting properties.
(Effects of material synthesis, crystal structure, and chemical composition)
引用本文:
TAO Qian;SHEN Jing-Qin;LI Lin-Jun;LIN Xiao;LUO Yong-Kang;CAO Guang-Han;XU Zhu-An. Upper Critical Fields and Anisotropy of BaFe1.9Ni0.1As2 Single Crystals[J]. 中国物理快报, 2009, 26(9): 97401-097401.
TAO Qian, SHEN Jing-Qin, LI Lin-Jun, LIN Xiao, LUO Yong-Kang, CAO Guang-Han, XU Zhu-An. Upper Critical Fields and Anisotropy of BaFe1.9Ni0.1As2 Single Crystals. Chin. Phys. Lett., 2009, 26(9): 97401-097401.
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