<i>PowderX</i>: Windows-95-based program for powder X-ray diffraction data processing

Dong, C.

doi:10.1107/s0021889899003039

Cited by 654 publications

(332 citation statements)

References 8 publications

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“…As we can see, only the samples with high doping levels have the impurity phase PtAs 2 . By fitting the XRD data to the structure with the software Powder-X, 21 we get the lattice constants of BaFe 2−x Pt x As 2 . In Fig.1 (b)-(c), we show a-and c-axes lattice parameters for the BaFe 2−x Pt x As 2 samples.…”

Section: A X-ray Diffractionmentioning

confidence: 99%

Superconductivity induced by doping platinum inBaFe2As2

Zhu

Han

et al. 2010

Phys. Rev. B

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By substituting Fe with the 5d-transition metal Pt in BaFe2As2, we have successfully synthesized the superconductors BaFe2−xPtxAs2. The systematic evolution of the lattice constants indicates that the Fe ions were successfully replaced by Pt ions. By increasing the doping content of Pt, the antiferromagnetic order and structural transition of the parent phase is suppressed and superconductivity emerges at a doping level of about x = 0.02. At a doping level of x = 0.1, we get a maximum transition temperature Tc of about 25 K. While even for this optimally doped sample, the residual resistivity ratio (RRR) is only about 1.35, indicating a strong impurity scattering effect. We thus argue that the doping to the Fe-sites naturally leads to a high level impurity scattering, although the superconductivity can still survive at about 25 K. The synchrotron powder x-ray diffraction shows that the resistivity anomaly is in good agreement with the structural transition. The superconducting transitions at different magnetic fields were also measured at the doping level of about x = 0.1, yielding a slope of -dHc2/dT = 5.4 T/K near Tc. Finally a phase diagram was established for the Pt doped 122 system. Our results suggest that superconductivity can also be easily induced in the FeAs family by substituting the Fe with Pt, with almost the similar maximum transition temperatures as doping Ni, Co, Rh and Ir.

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Section: A X-ray Diffractionmentioning

confidence: 99%

Superconductivity induced by doping platinum inBaFe2As2

Zhu

Han

et al. 2010

Phys. Rev. B

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“…The precipitated fine particles were characterized by XRD for structural determination and estimation of crystallite size. XRD patterns were analyzed and indexed using powder X software 23 . All experimental peaks were matched with the theoretically generated one and indexed.…”

Section: Physical Characterizationmentioning

confidence: 99%

“…Figure 2 shows that the lattice constant increases with increase in zinc concentration. The crystallite size (D XRD ) was estimated bythe Debye -Scherrer formula 23 using the full width at half maximum value of the respective indexed peaks. The average crystallite size (D aveXR ) decreases from 8.95 to 6.92 nm when the partial substitution of zinc increases (x = 0 to x = 1.0).…”

Section: Physical Characterizationmentioning

confidence: 99%

Synthesis of nickel zinc iron nanoparticles by coprecipitation technique

2010

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Nanoparticles nickel ferrite of size 6 -8 nm, synthesized by the coprecipitation method with x varying from 0 to 1.0. The powder samples were characterized by XRD, VSM and FTIR. The average crystallite sizes of the particles were determined from X-ray diffraction. X-ray analysis showed that the samples were cubic spinel. The lattice constant (a o ) increased with the increase in zinc substitution. The specific saturation magnetization (M S ) of the particles was measured at room temperature. The magnetic parameter of M S , was found to decrease with the increase in zinc substitution. Fourier transform infrared spectroscopy (FTIR) spectra of the Ni 1-x Zn x Fe 2 O 4 with x = 0, 0.5, 1 in the range 400 -4000 cm -1 were reported. The spinel structure and the crystalline water adsorption of Ni 1-x Zn x Fe 2 O 4 nanoparticles were studied by using FTIR.

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“…Only small amount of SrF 2 impurity phase was detected. By using the software of Powder-X, 22 we took a general fit to the XRD data of this sample and the lattice constants were deter- …”

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confidence: 99%

SrFeAsF as a parent compound for iron pnictide superconductors

Han

Zhu

et al. 2008

Phys. Rev. B

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We have successfully synthesized the fluo-arsenide SrFeAsF, a new parent phase with the ZrCuSiAs structure. The temperature dependence of resistivity and dc magnetization both reveal an anomaly at about Tan = 173 K, which may correspond to the structural and/or Spin-Density-Wave (SDW) transition. Strong Hall effect and moderate magnetoresistance were observed below Tan. Interestingly, the Hall coefficient RH is positive below Tan, which is opposite to the cases in the two parent phases of FeAs-based systems known so far, i.e., LnFeAsO (Ln = rare earth elements) and (Ba, Sr)Fe2As2 where the Hall coefficient RH is negative. This strongly suggests that the gapping of the Fermi surface induced by the SDW order leaves one of the hole pockets fully or partially ungapped in SrFeAsF. Our data show that it is possible for the parent phases of the arsenide superconductors to display dominant carriers that are either electronlike or holelike.PACS numbers: 74.70. Dd, 74.25.Fy, 75.30.Fv, 74.10.+v The discovery of superconductivity in the quaternary compound LaFeAsO 1−x F x which is abbreviated as the FeAs-1111 phase, has attracted great attentions in the fields of condensed matter physics and material sciences.1 The family of the FeAs-based superconductors has been extended rapidly. As for the FeAs-1111 phase, most of the discovered superconductors are characterized as electron-doped ones and the superconducting transition temperature has been quickly raised to T c = 55∼ 56 K via replacing lanthanum with other rare earth elements. 2,3,4,5,6,7 Meanwhile, the first holedoped superconductor La 1−x Sr x FeAsO with T c ≈ 25 K was discovered, 8,9 followed with the observation of superconductivity in hole-doped Nd 1−x Sr x FeAsO 10 and Pr 1−x Sr x FeAsO.11 Later on, (Ba, Sr) 1−x K x Fe 2 As 2 which is denoted as FeAs-122 for simplicity 12,13,14 , and Li x FeAs as an infinite layered structure (denoted as FeAs-111) were discovered. 15,16,17 It is assumed that the superconductivity both in the FeAs-1111 phase and FeAs-122 phase is intimately connected with a Spin-DensityWave (SDW) anomaly in the FeAs layers.12,18 For undoped LaFeAsO, an SDW-driven structural phase transition around 150 K was found.19 It seems that any new parent phase will initiate a series of new superconductors by doping it away from the state with features of a bad metal and the SDW order.In this paper, we report the discovery of a new FeAsbased layered compound SrFeAsF which has the ZrCuSiAs structure. As we know SrZnPF is a compound with the ZrCuSiAs structure 20 . We replace the ZnP sheets with FeAs sheets and get a new compound of SrFeAsF. The compound SrFeAsF has the tetragonal space group P4/nmm at 300 K. Both the resistivity and the dc magnetic susceptibility exhibit a clear anomaly at about 173 K, which is attributed to the structural and/or SDW transition. Surprisingly, a positive Hall coefficient R H has been found implying a dominant conduction by holelike charge carriers in this parent phase.The SrFeAsF samples were prepared using a two-step solid s...

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PowderX: Windows-95-based program for powder X-ray diffraction data processing

Cited by 654 publications

References 8 publications

Superconductivity induced by doping platinum inBaFe2As2

Superconductivity induced by doping platinum inBaFe2As2

Synthesis of nickel zinc iron nanoparticles by coprecipitation technique

SrFeAsF as a parent compound for iron pnictide superconductors

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