TY - JOUR
T1 - Upper critical field of the pressure-induced superconductor EuFe 2As2
AU - Kurita, Nobuyuki
AU - Kimata, Motoi
AU - Kodama, Kota
AU - Harada, Atsushi
AU - Tomita, Megumi
AU - Suzuki, Hiroyuki S.
AU - Matsumoto, Takehiko
AU - Murata, Keizo
AU - Uji, Shinya
AU - Terashima, Taichi
PY - 2011/3/8
Y1 - 2011/3/8
N2 - We have carried out high-field resistivity measurements up to 27 T in EuFe2As2 at P=2.5 GPa, a virtually optimal pressure for the P-induced superconductivity, where Tc=30 K. The B c2-Tc phase diagram has been constructed in a wide temperature range with a minimum temperature of 1.6 K (≈0.05 × T c), for both B ab (Bc2ab) and B c (Bc2c). The upper critical fields Bc2ab(0) and Bc2c(0), determined by the onset of resistive transitions, are 25 and 22 T, respectively, which are significantly smaller than those of other Fe-based superconductors with similar values of Tc. The small B c2(0) values and the Bc2(T) curves with positive curvature around 20 K can be explained by a multiple pair-breaking model that includes the exchange field due to the magnetic Eu2+ moments. The anisotropy parameter, Γ=Bc2ab/Bc2c, in EuFe2As2 at low temperatures is comparable to that of other "122" Fe-based systems.
AB - We have carried out high-field resistivity measurements up to 27 T in EuFe2As2 at P=2.5 GPa, a virtually optimal pressure for the P-induced superconductivity, where Tc=30 K. The B c2-Tc phase diagram has been constructed in a wide temperature range with a minimum temperature of 1.6 K (≈0.05 × T c), for both B ab (Bc2ab) and B c (Bc2c). The upper critical fields Bc2ab(0) and Bc2c(0), determined by the onset of resistive transitions, are 25 and 22 T, respectively, which are significantly smaller than those of other Fe-based superconductors with similar values of Tc. The small B c2(0) values and the Bc2(T) curves with positive curvature around 20 K can be explained by a multiple pair-breaking model that includes the exchange field due to the magnetic Eu2+ moments. The anisotropy parameter, Γ=Bc2ab/Bc2c, in EuFe2As2 at low temperatures is comparable to that of other "122" Fe-based systems.
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U2 - 10.1103/PhysRevB.83.100501
DO - 10.1103/PhysRevB.83.100501
M3 - Article
AN - SCOPUS:79961046357
SN - 0163-1829
VL - 83
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 10
M1 - 100501
ER -