Observation of the Josephson Effect in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Pb</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mi>Ba</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="bold">K</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Fe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>Single Crystal Junctions

Zhang, Xiaohang; Oh, Yoon Seok; Liu, Yong; Li, Yan; Kim, Kee Hoon; Greene, R. L.; Takeuchi, Ichiro

doi:10.1103/physrevlett.102.147002

Cited by 98 publications

(68 citation statements)

References 39 publications

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“…Resistivity measurements ͓Fig. 1͑a͔͒ showed that the superconducting transitions were very sharp and the T C s were approximately 17 K for SrFe 1 ͒ single crystals confirms that the transport is dominated by electrons ͑holes͒, which is consistent with the dopant type of the compound and in qualitative agreement with previous reports. 12,13 In both types of single crystals, all Hall resistivity curves display a strong linear dependence in magnetic fields up to 7 T. As an example, Fig.…”

supporting

confidence: 78%

“…14͒ into account, the dimension of the effective coupling area ͑W͒, through which the Josephson current is flowing, is estimated to be about 25 m for the bicrystal junction, consistent with the values obtained from our previous Pb/ Ba 1−x K x Fe 2 As 2 junctions. 1 As discussed previously, 1 the effective junction area where the current is flowing could be significantly smaller than the nominally intended junction area defined by the overlapping of the crystals because much of the crystal surface layer is oxidized and thus nonsuperconducting. In particular, preliminary low temperature scanning tunnel microscope experiments performed on Ba 1−x K x Fe 2 As 2 single crystals suggested significant degradation in superconductivity of the surface after a period of exposure in ambient atmosphere.…”

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confidence: 99%

“…1 In this letter, we report the observation of the Josephson effect in bicrystal junctions along the c-axis between electron-doped ͑e-doped͒ and hole-doped ͑h-doped͒ pnictide single crystals. The critical currents are completely modulated by applying an inplane external magnetic field.…”

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confidence: 99%

“…1 axis edges. Each crystal was soldered on a sapphire substrate by indium, and two separated electrical contacts were made on the back of the crystals.…”

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Josephson effect between electron-doped and hole-doped iron pnictide single crystals

Zhang

Saha

Butch

et al. 2009

Applied Physics Letters

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confidence: 78%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…1 axis edges. Each crystal was soldered on a sapphire substrate by indium, and two separated electrical contacts were made on the back of the crystals.…”

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confidence: 99%

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Josephson effect between electron-doped and hole-doped iron pnictide single crystals

Zhang

Saha

Butch

et al. 2009

Applied Physics Letters

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“…An iron pnictide has the hole and electron Fermi pockets at Γ point and M point, respectively, with a wavevector of (π, π) connected. And a number of experiments have suggested a spin singlet pairing between the hole Fermi pocket and the electron Fermi pocket [37][38][39]. We have carried out density functional theory (DFT) electronic structure calculations for Co/Ir-doped BaFe 2 As 2 .…”

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confidence: 99%

Microstructure and superconductivity of Ir-doped BaFe2As2 superconductor

Wang

Shi

Yan

et al. 2010

Applied Physics Letters

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Polycrystalline samples with nominal composition of Ba(Fe 1-x Ir x ) 2 As 2 (x=0. 10, 0.15, and 0.20) were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity, and magnetization measurements. XRD and SEM results showed that almost single phase samples were obtained. Bulk superconductivity with T C~2 8 K was observed in the x=0.10 sample. T C~2 8 K is the highest superconducting critical temperature among the reported data for electron-doped AFe 2 As 2 -type (A=Ca, Sr, and Ba) superconductors. The upper critical field H c2 (0) reaches as high as 65 T for the x=0.10 sample. The underlying physics is discussed in connection with Co-doping case.PACS numbers: 74.70. Dd, 74.25.Fy, 74.62.Dh, 74.62.Bf * Corresponding author. Tel.: +86-10-6251-1523.E-mail address: tszhao@ruc.edu.cn (T.-S. Zhao).-1 -Since the recent discovery of superconductivity in the F-doped RFeAsO (R = La, Ce, Pr, Nd, Sm, and Gd ) and Th-doped GdFeAsO with the highest T C up to as high as 55-56 K [1-6], the FeAs-based superconductors have attracted much attention. Another family of oxygen-free FeAs-based compounds with the ThCr 2 Si 2 -type structure such as K or Na-doped AFe 2 As 2 (A = Ca, Sr, Ba, and Eu) and Co-doped AFe 2 As 2 (A = Sr, Ba) were found to be superconductors with the highest T C up to 38 K [7][8][9][10][11][12][13]. The electron-doped Ba(Fe, Co) 2 As 2 system has been extensively studied and the temperature-composition phase diagram of this system has been determined by several groups [14][15][16][17][18][19][20][21]. The determined phase diagrams show a striking feature that there is a coexistence of antiferromagnetisim and superconductivity in an underdoped region. Very recently, a number of electron-doped Ba (Fe, M) 2 As 2 (M = Ni, Ru, Rh, and Pd) [22][23][24][25] and Sr(Fe, M) 2 As 2 (M = Ni, Ru, Rh, Pd, and Ir) [26][27][28][29] compounds was also found to exhibit superconductivity.Among the electron-doped superconductors, a higher T C was observed in Co-doped BaFe Powder X-ray diffraction (XRD) using Cu K α radiation at room temperature was used to identify phase structure of the samples. Figure 1(a) shows the powder XRD patterns for Table I. It can be seen from Table I that the a-axis increases and the c-axis shrinks slightly with increasing the Ir content x, respectively.We have examined the microstructure and phase composition of the samples using a scanning electron microscope (SEM) (LEO 1450, Carl Zeiss SMT Ltd., Cambridge, UK) equipped with an energy dispersive X-ray (EDX) spectrometer. SEM micrographs show that, comparing with the undoped BaFe 2 As 2 , there is a gradual and considerable decrease in the grain size for the Ir-doped samples with increasing the Ir content. Figures 1(b) and 1(c) show the backscattered electron images for the samples with x = 0.10 and 0.20, respectively. It can be seen that there exists a small fraction of white phase as an impurity phase in the samples. Our EDX analysis shows that the white phase is IrAs 2 phase. In fact, a small pe...

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