Superconducting Properties of the Fe-Based Layered Superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>LaFeAsO</mml:mi><mml:mn>0.9</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">F</mml:mi><mml:mrow><mml:mn>0.1</mml:mn><mml:mo>−</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub></mml:math>

Chen, G. F.; Li, Z; Li, G.; Zhou, Jie; Wu, Dong; Dong, Jing; Hu, W. Z.; Zheng, P.; Chen, Zejun; Yuan, Huiqiu; Singleton, John; Luo, Jianlin; Wang, N. L.

doi:10.1103/physrevlett.101.057007

Cited by 172 publications

(140 citation statements)

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“…7 [38] (see the plots in Fig. 7) and LaFeAsO 0.9 F 0.1-δ [39]. The carrier density monotonically decreases on cooling over 3 orders of the magnitude to 9.9×10 17 cm -3 (5 K), corresponds to 0.0003 electrons per unit cell.…”

Section: Results and Discusionmentioning

confidence: 99%

Magnetic and electrical properties and carrier doping effects on the iron-based host compound Sr2ScFeAsO3

et al. 2011

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Additional charge carriers were introduced to the iron oxyarsenide Sr 4 Sc 2 Fe 2 As 2 O 6 under a high-pressure condition, followed by measurements of electrical resistivity, Hall coefficient, and magnetic susceptibility. The host compound Sr 4 Sc 2 Fe 2 As 2 O 6 shows metallic conductivity down to ~200 K and turns to show a semiconducting-like conductivity accompanied by a positive magneto-resistance (22% at 70 kOe). Although the carrier density is comparable at 300 K (5.9×10 21 cm -3 ) with that of the other Fe-based superconductors, no superconductivity appears down to 2 K. This is primarily because the net carrier density decreases over 3 orders of magnitude on cooling and additionally a possible magnetic order at ~120 K prevents carriers from pairing. The properties were altered largely by introducing the additional carriers.

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Section: Results and Discusionmentioning

confidence: 99%

Magnetic and electrical properties and carrier doping effects on the iron-based host compound Sr2ScFeAsO3

et al. 2011

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“…7,8 It should be emphasized that these are rich structure types and that there is no doubt much compositional space that remains to be explored. 9,10 In this regard, besides the FeAs based phases, superconductivity is also observed in Ni based materials, including LaNiPO, 11,12 pure, fluorine or Sr doped LaNiAsO, 13,14,15 and LaNiBiO. 16 Interestingly, both Ni and Fe are ambient temperature elemental ferromagnets, and many Fe and Ni compounds show magnetism.…”

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confidence: 99%

Electron-phonon superconductivity in LaNiPO

Subedi¹,

Singh²,

Du³

2008

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“…Indeed, first measurements of the upper critical field B c2 at low fields B < 7T have yielded a slope B c2 / (T c ) = dB c2 /dT º 2T/K near T c , for both La and Sm based oxypnictides [2][3][4][5][6]. From the conventional one-band Werthamer-Helfand-Hohenberg (WHH) theory [20] such slopes already imply rather high values B c2 (0) = 0.69T c B c2…”

mentioning

confidence: 99%

Two-band superconductivity in LaFeAsO0.89F0.11 at very high magnetic fields

Hunte

Jaroszyński

Gurevich

et al. 2008

Nature

566

564

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[7,8] These discoveries have generated much interest in the mechanisms and manifestations of unconventional superconductivity in the family of doped quaternary layered oxypnictides LOMPn (L = La, Pr, Ce, Sm; M = Mn, Fe, Co, Ni; Pn=P, As) [9,10], because many features of these materials clearly set them apart from other superconductors. First, ab-initio calculations indicate that superconductivity originates from the d-orbitals of what would normally be expected to be pairbreaking magnetic Fe ions, suggesting that new non-phonon pairing mechanisms are responsible for the high T c [11,12]. Second, F-doped LaFeAsO is a semimetal, which exhibits strong ferromagnetic and antiferromagnetic fluctuations and a possible spin density wave instability around 150K in the parent undoped LaFeAsO [5,[13][14][15][16]. And third, superconductivity emerges on several disconnected pieces of the Fermi surface [11,12,17,18], thus exhibiting the multi-gap pairing, which has recently attracted so much attention in MgB 2 [19].Given the importance of magnetic correlations in the doped oxypnictides, transport measurements at very high magnetic fields are vital to probe the mechanisms of superconductivity. Indeed, first measurements of the upper critical field B c2 at low fields B < 7T have yielded a slope B c2 / (T c ) = dB c2 /dT º 2T/K near T c , for both La and Sm based oxypnictides [2][3][4][5][6]. From the conventional one-band Werthamer-Helfand-Hohenberg (WHH) theory [20] such slopes already imply rather high values B c2 (0) = 0.69T c B c2/ º 36T for LaFeAsO 0.89 F 0.1 , B c2 (0) º 59.3T for SmFeAsO 0.89 F 0.1 , and B c2 (0) º 72 T for PrFeAsO 0.89 F 0.1 , all well above B c2 of Nb 3 Sn. However, studies of the high-field superconductivity in MgB 2 alloys have shown that the upward curvature of B c2 (T) resulting from the multiband effects can significantly increase B c2 (0) as compared to the WHH one-band extrapolation (see, e.g., the review [21] and references therein). To address these important issues, we have performed high-field dc transport measurements on LaFeAsO 0.89 F 0.1 samples up to 45T. We show that B c2 (T) indeed exhibits two-gap behavior similar to that in MgB 2 , and B c2 (0) values exceed the WHH extrapolation by the factor ~ 2. Moreover, the observed B c2 (0) also exceeds the BCS paramagnetic limitPolycrystalline LaFeAsO 0.89 F 0.11 samples were made by solid state synthesis [4]. A sample ~ 3 x 1 x 0.5 mm was used for our four probe transport measurements in the 45T Hybrid magnet at the NHMFL, supplemented by low field measurements in a 9T superconducting magnet. Our low-field data agreed well with the earlier data taken at ORNL on the same sample [4], indicating its good temporal and atmospheric stability. The 45T Hybrid magnet was swept only from 11.5T to 45T due to the constant 11.5T background of the outsert magnet while lower fields were swept from 0T to 9T in a PPMS with resistivity measured in AC mode using a 5mA excitation current, whereas the high field resistance R(B) was measured by a Keithley nanovo...

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Superconducting Properties of the Fe-Based Layered SuperconductorLaFeAsO0.9F0.1−δ

Cited by 172 publications

References 14 publications

Magnetic and electrical properties and carrier doping effects on the iron-based host compound Sr2ScFeAsO3

Magnetic and electrical properties and carrier doping effects on the iron-based host compound Sr2ScFeAsO3

Electron-phonon superconductivity in LaNiPO

Two-band superconductivity in LaFeAsO0.89F0.11 at very high magnetic fields

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