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Title: Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}

Abstract

The ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4} has been prepared by arc melting. This compound takes a body-centered lattice with an orthorhombic unit cell with the lattice parameters of a=4.2200(3) A, b=4.3850(3) A, and c=25.003(2) A. The crystal structure of La{sub 3}Pd{sub 4}Ge{sub 4} is U{sub 3}Ni{sub 4}Si{sub 4}-type with the space group of Immm, consisting of the combination of structural units of AlB{sub 2}-type and BaAl{sub 4}-type layers. This compound is a type-II superconductor with a critical temperature (T{sub c}) of 2.75 K. The lower critical field H{sub c1}(0) is estimated to be 54 Oe. The upper critical field H{sub c2}(0) estimated by linear extrapolation of the H{sub c2}(T) curves is about 4.0 kOe, whereas the Werthamer-Hefland-Hohemberg theory gives H{sub c2}(0){sup WHH}=3.0 kOe. This is an interesting observation of superconductivity in the compounds with U{sub 3}Ni{sub 4}Si{sub 4}-type structure. The coherence length {xi}(0) of 330 A and the penetration depth {lambda}(0) of 2480 A are derived.

Authors:
; ;  [1];  [2]
  1. Superconducting Materials Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
  2. Materials Analysis Station, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
Publication Date:
OSTI Identifier:
20787751
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 72; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevB.72.214520; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM BORIDES; COHERENCE LENGTH; CRITICAL FIELD; EXTRAPOLATION; GERMANIUM ALLOYS; LANTHANUM ALLOYS; LATTICE PARAMETERS; LAYERS; MELTING; ORTHORHOMBIC LATTICES; PALLADIUM ALLOYS; PENETRATION DEPTH; SUPERCONDUCTIVITY; TETRAGONAL LATTICES; TRANSITION TEMPERATURE; TYPE-II SUPERCONDUCTORS

Citation Formats

Fujii, H., Mochiku, T., Takeya, H., and Sato, A.. Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}. United States: N. p., 2005. Web. doi:10.1103/PHYSREVB.72.2.
Fujii, H., Mochiku, T., Takeya, H., & Sato, A.. Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}. United States. doi:10.1103/PHYSREVB.72.2.
Fujii, H., Mochiku, T., Takeya, H., and Sato, A.. Thu . "Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}". United States. doi:10.1103/PHYSREVB.72.2.
@article{osti_20787751,
title = {Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}},
author = {Fujii, H. and Mochiku, T. and Takeya, H. and Sato, A.},
abstractNote = {The ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4} has been prepared by arc melting. This compound takes a body-centered lattice with an orthorhombic unit cell with the lattice parameters of a=4.2200(3) A, b=4.3850(3) A, and c=25.003(2) A. The crystal structure of La{sub 3}Pd{sub 4}Ge{sub 4} is U{sub 3}Ni{sub 4}Si{sub 4}-type with the space group of Immm, consisting of the combination of structural units of AlB{sub 2}-type and BaAl{sub 4}-type layers. This compound is a type-II superconductor with a critical temperature (T{sub c}) of 2.75 K. The lower critical field H{sub c1}(0) is estimated to be 54 Oe. The upper critical field H{sub c2}(0) estimated by linear extrapolation of the H{sub c2}(T) curves is about 4.0 kOe, whereas the Werthamer-Hefland-Hohemberg theory gives H{sub c2}(0){sup WHH}=3.0 kOe. This is an interesting observation of superconductivity in the compounds with U{sub 3}Ni{sub 4}Si{sub 4}-type structure. The coherence length {xi}(0) of 330 A and the penetration depth {lambda}(0) of 2480 A are derived.},
doi = {10.1103/PHYSREVB.72.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 21,
volume = 72,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}
  • An electron and X-ray diffraction investigation of powder and single crystals shows that U{sub 3}Co{sub 4}Ge{sub 7} crystallizes in a tetragonal structure with the space group I4/mmm,: a = 410.87(7) pm, c = 2747.7(9) pm, V = 0.4638(2) nm{sup 3}, Z = 2, R = 0.039 for the Rietveld refinement, and R = 0.050 for the single-crystal study (373 F values and 21 variables). Its structure shows some similarities with that of Eu{sub 2}Pt{sub 7}AlP{sub 4-x} and can be interpreted as an intergrowth of CaBe{sub 2}Ge{sub 2-} and Cu{sub 3}Au-type blocks. U{sub 3}Co{sub 4}Ge{sub 7} orders ferro- or ferrimagnetically atmore » 21.5(5) K and exhibits another magnetic transition below 20.5(3) K. Its properties are compared to those observed for other ternary germanides such as UCo{sub 2}Ge{sub 2} and UCoGe.« less
  • The germanide Yb{sub 2}Ru{sub 3}Ge{sub 4} was synthesized from the elements using the Bridgman crystal growth technique. The monoclinic Hf{sub 2}Ru{sub 3}Si{sub 4} type structure was investigated by X-ray powder and single crystal diffraction: C2/c, Z=8, a=1993.0(3) pm, b=550.69(8) pm, c=1388.0(2) pm, {beta}=128.383(9){sup o}, wR {sub 2}=0.0569, 2047 F {sup 2} values, and 84 variables. Yb{sub 2}Ru{sub 3}Ge{sub 4} contains two crystallographically independent ytterbium sites with coordination numbers of 18 and 17 for Yb1 and Yb2, respectively. Each ytterbium atom has three ytterbium neighbors at Yb-Yb distances ranging from 345 to 368 pm. The shortest interatomic distances occur for themore » Ru-Ge contacts. The three crystallographically independent ruthenium sites have between five and six germanium neighbors in distorted trigonal bipyramidal (Ru1Ge{sub 5}) or octahedral (Ru2Ge{sub 6} and Ru3Ge{sub 6}) coordination at Ru-Ge distances ranging from 245 to 279 pm. The Ru2 atoms form zig-zag chains running parallel to the b-axis at Ru2-Ru2 of 284 pm. The RuGe{sub 5} and RuGe{sub 6} units are condensed via common edges and faces leading to a complex three-dimensional [Ru{sub 3}Ge{sub 4}] network. - Graphical abstract: Condensation of the Ru1Ge{sub 5}, Ru2Ge{sub 6}, and Ru3Ge{sub 6} units in the structure of Yb{sub 2}Ru{sub 3}Ge{sub 4}.« less
  • A combinatorial-topological analysis of the La{sub 3}Ga{sup [6]}Ga{sub 4}{sup [4]}Ge{sup [4]}O{sub 14} and La{sub 3}Ge{sup [6]}Ge{sub 2}{sup [5]}Ge{sub 2}{sup [4]}Ga{sup [4]}O{sub 16} gallogermanates, which have MT and MPT microporous frameworks composed of M octahedra (GeO{sub 6}, GaO{sub 6}), T tetrahedra (GeO{sub 4}, GaO{sub 4}), and P pyramids (GeO{sub 5}), is performed using the method of coordination sequences with the TOPOS 3.2 program package. It is established that the La{sub 3}Ga{sup [6]}Ga{sub 4}{sup [4]}Ge{sup [4]}O{sub 14} gallogermanate is characterized by a crystal-forming net 6 6 6 (of the graphite type). A new type of the binodal net 6 10 1 0more » + 6 10 (2: 1) is revealed in the La{sub 3}Ge{sup [6]}Ge{sub 2}{sup [5]}Ge{sub 2}{sup [4]}Ga{sup [4]}O{sub 16} gallogermanate. The cyclic cluster precursors composed of six polyhedra with a lanthanum template atom at the center of the LaMT{sub 5} and LaMP{sub 3}T{sub 3} clusters are identified by the two-color decomposition of the nets in the structures of the La{sub 3}Ga{sup [6]}Ga{sub 4}{sup [4]}Ge{sup [4]}O{sub 14} and La{sub 3}Ge{sup [6]}Ge{sub 2}{sup [5]}Ge{sub 2}{sup [4]}Ga{sup [4]}O{sub 16} gallogermanates. The coordination numbers of the cluster precursors in these structures are found to be equal to 6 and 4 for two-dimensional nets and 8 and 6 for three-dimensional nets, respectively.« less
  • Tm/sub 3/Cu/sub 4/Sn/sub 4/ has been studied by single - crystal X - ray diffraction analysis. The structure is of a new type with space group C2/m and Z = 2 : a = 16.119(2), b = 4.3935(6), c = 6.896(1) A, ..beta.. = 115.88(2)/sup 0/, D /SUB x/ = 9.32 Mgm/sup -3/, ..mu..(MoK..cap alpha..) = 52 mm/sup -1/, F(000) = 1045, R = 0.056 for 558 independant reflexions (R /SUB w/ = 0.058). Tm/sub 3/Cu/sub 4/Sn/sub 4/ is a monoclinic distorded variety of the Gd/sub 3/Cu/sub 4/Ge/sub 4/ structure typ0e. Seven other compounds were characterized : Sc/sub 3/Cu/sub 4/Ge/submore » 4/ and R.E/sub 3/Cu/sub 4/Sn/sub 4/ where R.E. = Y, Gd, Tb, Dy, Ho, Er, isostructural with Gd/sub 3/Cu/sub 4/Sn/sub 4/.« less
  • The whole 500 °C isothermal section of the La–Mg–Ge ternary system was constructed. The existence and crystal structure of three ternary compounds were confirmed: La{sub 2+x}Mg{sub 1−x}Ge{sub 2} (τ{sub 2}, P4/mbm, tP10–Mo{sub 2}FeB{sub 2}, 0≤x≤0.25), La{sub 4}Mg{sub 5}Ge{sub 6} (τ{sub 3}, Cmc2{sub 1}, oS60–Gd{sub 4}Zn{sub 5}Ge{sub 6}) and La{sub 4}Mg{sub 7}Ge{sub 6} (τ{sub 4}, C2/m, mS34, own structure type). Five novel compounds were identified and structurally characterized: La{sub 11}Mg{sub 2}Ge{sub 7} (τ{sub 1}, P4{sub 2}/ncm, tP88-8, own structure type, a=1.21338(5), c=1.57802(6) nm), LaMg{sub 3−x}Ge{sub 2} (τ{sub 5}, P3{sup ¯}1c, hP34-0.44, own structure type, x=0.407(5), a=0.78408(4), c=1.45257(7) nm), La{sub 6}Mg{sub 23}Gemore » (τ{sub 6}, Fm3{sup ¯}m, cF120–Zr{sub 6}Zn{sub 23}Si, a=1.46694(6) nm), La{sub 4}MgGe{sub 10−x} (τ{sub 7}, x=0.37(1), C2/m, mS60-1.46, own structure type, a=0.88403(8), b=0.86756(8), c=1.7709(2) nm, β=97.16°(1) and La{sub 2}MgGe{sub 6} (τ{sub 8}, Cmce, oS72–Ce{sub 2}(Ga{sub 0.1}Ge{sub 0.9}){sub 7}, a=0.8989(2), b=0.8517(2), c=2.1064(3) nm). Disordering phenomena were revealed in several La–Mg–Ge phases in terms of partially occupied sites. The crystal structures of La{sub 11}Mg{sub 2}Ge{sub 7} and LaMg{sub 3−x}Ge{sub 2} are discussed in details. The latter is a √3a×√3a×2c superstructure of the LaLi{sub 3}Sb{sub 2} structure type; the symmetry reduction scheme is shown in the Bärnighausen formalism terms. - Graphical abstract: La–Mg–Ge isothermal section at 500 °C and group–subgroup relation between the LaLi{sub 3}Sb{sub 2} (parent type) and LaMg{sub 3−x}Ge{sub 2} (derivative) structures. - Highlights: • Novel La−Mg−Ge compounds structure determination from X-ray single crystal data. • Disordering phenomena as common features of the studied germanides. • Bärnighausen formalism as a useful tool for accurate structure determination. • Full isothermal section of the La–Mg–Ge ternary system at 500 °C.« less