Upper Critical Fields and Anisotropy of BaFe 1.9 Ni 0.1 As 2 Single Crystals

Autor:	Tao Qian, Luo Yong-Kang, Xu Zhu-An, Lin Xiao, Shen Jing-Qin, Cao Guang-Han, LI Lin-Jun
Rok vydání:	2009
Předmět:	Physics Superconductivity Paramagnetism Condensed matter physics Magnetoresistance Magnetism Electrical resistivity and conductivity Condensed Matter::Superconductivity General Physics and Astronomy Atmospheric temperature range Anisotropy Critical field
Zdroj:	Chinese Physics Letters. 26:097401
ISSN:	1741-3540 0256-307X
DOI:	10.1088/0256-307x/26/9/097401
Popis:	Temperature dependence of the upper critical magnetic field (Hc2) near Tc of 20 K 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 8 T. The upper critical fields at zero temperature estimated by the Werthamer-Helfand-Hohenberg (WHH) formula are μ0H||c2(0) = 137 T and μ0H⊥c2(0) = 51 T, both exceeding the weak-coupling Pauli paramagnetic limit (μ0Hp = 1.84Tc). However, the WHH formula could overestimate the μ0H||c2(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.
Databáze:	OpenAIRE
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