Polymorphism and superconductivity of La<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ir</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Braun, H. F.; Engel, N.; Parthé, E.

doi:10.1103/physrevb.28.1389

Cited by 116 publications

(52 citation statements)

References 10 publications

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“…The most commonly observed structure types for compounds of the composition AM 2 X 2 (A = electropositive element, M = transition or main group metal, and X=element from Group 13,14 or 15) are the tetragonal ThCr 2 Si 2 (I4/mmm), closely related CaBe 2 Ge 2 (tetragonal, P4/nmm), and trigonal CaAl 2 Si 2 (P3m1) structure types. 18,22,[26][27][28][29] AM 2 X 2 phases can theoretically achieve a remarkable structural diversity, depending on factors such as the relative sizes and coordination preferences of the large number of elements that can be accommodated, and by taking advantage of the variable connectivity possible for main group polyanions. Thus, our group has recently reported the synthesis and structural characterization of hexagonal EuIn 2 Pn 2 compounds (Pn = P, As; P6 3 /mmc), 8,14 which display structural similarities to the three common AM 2 X 2 structure types.…”

Section: Resultsmentioning

confidence: 99%

“…Many of these interesting properties are found in materials of composition AM 2 X 2 (M = transition or main group element, X=Group 13-15 element), which is a particularly diverse structural class. 8,14,[18][19][20][21][22] Recent discovery of colossal magnetoresistance (CMR) in several of the magnetically ordering AM 2 X 2 compounds (e.g., EuIn 2 P 2 and EuIn 2 As 2 ), 8,14 provides incentive for additional research into these types of compounds in order to provide correlations between material composition, structure, and the observed electrical, magnetic, and/or magneto-electronic properties.…”

Section: Introductionmentioning

confidence: 99%

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Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

et al. 2009

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Single crystals of EuGa 2 Pn 2 (Pn=P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a = 9.2822(9) Å , b=3.8967(4) Å , c=12.0777(11) Å , β=95.5220(10)°, R1 = 0.0148, wR2 = 0.0325 (EuGa 2 P 2 ) and a = 9.4953(7) Å , b = 4.0294(3) Å , c = 12.4237(9) Å , β = 95.3040(10)°, R1 = 0.0155, wR2 = 0.0315 (EuGa 2 As 2 )). The structures consist of alternating layers of two-dimensional Ga 2 Pn 2 anions and Eu cations. The anion layers are composed of Ga 2 Pn 6 staggered, ethane-like moieties having a rare Ga-Ga bonding motif; these moieties are connected in a complex fashion by means of shared Pn atoms. Both structures show small residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (<2%) where most of the atoms are the same, but there is a difference in bonding that leads to one-dimensional ribbons of parallel Ga 2 Pn 6 staggered, ethane-like moieties. The compounds can be understood within the Zintl formalism, but show metallic resistivity. Magnetization measurements performed on single crystals show low-temperature magnetic anisotropy as well as multiple magnetic ordering events that occur at and below 24 and 20 K for the phosphorus and arsenic analogs, respectively. The magnetic coupling between Eu ions is attributed to indirect exchange via an RKKY interaction, which is consistent with the metallic behavior. The compounds display large negative magnetoresistance of up to -80 and -30%

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

et al. 2009

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“…Letzterer ist z. B. bei LaIr 2 Si 2 die Hochtemperaturmodifikation [4]. SrPd 2 Sb 2 kristallisiert dagegen bei Raumtemperatur in der CaBe 2 Ge 2 -Struktur, der ThCr 2 Si 2 -Typ wird erst oberhalb von 730…”

Section: Introductionunclassified

Neue Arsenide mit ThCr₂Si₂- oder einer damit verwandten Struktur: Die Verbindungen ARh₂As₂ (A: Eu, Sr, Ba) und BaZn₂As₂ / New Arsenides with ThCr₂Si₂-type or Related Structures: The Compounds ARh₂As₂ (A: Eu, Sr, Ba) and BaZn₂As₂

Hellmann

Löhken

Wurth

et al. 2007

Zeitschrift Für Naturforschung B

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Four new arsenides of rhodium and zinc were prepared by heating mixtures of the elements at high temperatures (1000 -1200 • C) and investigated by single crystal X-ray methods. EuRh 2 As 2 (a = 4.067(1), c = 11.319(2)Å) and BaRh 2 As 2 (a = 4.053(1), c = 12.770(3)Å) crystallize with the well-known ThCr 2 Si 2 -type (I4/mmm; Z = 2). Due to the rigid layers of RhAs 4 tetrahedra, and to the atomic size of europium and barium, the As-As distances between the layers with values of 2.97 and 3.66Å, respectively, are very long. SrRh 2 As 2 is polymorphic and undergoes two phase transitions at about 190 and 282 • C. Main features of the three crystal structures are also layers of RhAs 4 tetrahedra. At room temperature α-SrRh 2 As 2 (a = 5.676(1), b = 6.178(2), c = 11.052(2)Å) probably crystallizes with the BaNi 2 Si 2 -type (Cmcm; Z = 4), whereas β -SrRh 2 As 2 (a = 5.760(3), b = 6.067(4), c = 11.264(5)Å, Fmmm, Z = 4) forms a new orthorhombically distorted variant of the ThCr 2 Si 2 -type. Single crystals grown in a flux of lead and quenched at high temperature show that the γ-phase (a = 4.112(1), c = 11.431(6)Å) crystallizes with the ThCr 2 Si 2 -type. The same is true for the high temperature modification of BaZn 2 As 2 (β -phase; a = 4.120(1), c = 13.578(1)Å), whereas the already known α-BaZn 2 As 2 forms the α-BaCu 2 S 2 -type (Pnma; Z = 4) consisting of a 3D-network of edge-and vertex-sharing ZnAs 4 tetrahedra with Ba atoms in the voids of this network.

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“…It may change with temperature or with the nature of the M atoms. For example, Lalr2Si 2 has a low-temperature modification with ThCr2Si 2 type, but a high-temperature modification with CaBe2Ge 2 type (Braun, Engel & Parth+, 1983). According to Hofmann & Jeitschko (1983) the rare-earth-nickel (palladium) pnictides have the ThCr2Si 2 type if M = P, As, but the CaBe2Ge 2 type if M = Sb, Bi.…”

Section: Diseusslonmentioning

confidence: 99%

“…R TI4tITISpIM2, P4/nmm: this BaAl4-type derivative was first reported for CaBe2Ge2 (Eisenmann, May, M/iller & SchS.fer, 1972) and also occurs in the high-temperature modification of LaIr2Si 2 (Braun, Engel & Parth+, 1983). The structure can be interpreted as being built up by a periodic intergrowth of …”

Section: Rt2m 2 Compounds: Two Probable Structures and One With T-t Cmentioning

confidence: 99%

Ternary BaAl₄-type derivative structures

Parthé¹,

Chabot²,

Braun³

et al. 1983

Acta Crystallogr B Struct Sci

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Ternary BaAl4-type derivative stluctures are frequently found with rare-earth-transition-metal silicides and germanides with the rare-earth atoms occupying the Ba sites and the two other kinds of atoms distributed in ordered fashion on the A1 sites. The possible ternary BaA14-type derivative structures with the same unit cell as BaA14 are investigated. If it is assumed that transition-metal-transition-metal contacts are to be excluded only seven hypothetical BaAl4-type derivative structures are possible. Three of these are already known as ThCr2Si2, CaBe2Ge 2 and BaNiSn 3 types. Segments of these three structures and of other BaAl4-type derivative structures are found in various intergrowth structures. The BaA14-type derivative structures can be classified according to the type of coordination polyhedron around the transition metal, which can be a tetrahedron or a square pyramid. The tendency of the transition metal to have one or the other coordination polyhedron determines which BaAl4-type derivative structure is formed and explains also the occurrence of the HfFe2Si 2 and U2C03Si 5 types -BaAla-type derivative structures with larger unit cells.

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Polymorphism and superconductivity of LaIr2Si2

Cited by 116 publications

References 10 publications

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

Neue Arsenide mit ThCr₂Si₂- oder einer damit verwandten Struktur: Die Verbindungen ARh₂As₂ (A: Eu, Sr, Ba) und BaZn₂As₂ / New Arsenides with ThCr₂Si₂-type or Related Structures: The Compounds ARh₂As₂ (A: Eu, Sr, Ba) and BaZn₂As₂

Ternary BaAl₄-type derivative structures

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Polymorphism and superconductivity of LaIr2Si2

Cited by 116 publications

References 10 publications

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa2Pn2 (Pn = P, As)

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa2Pn2 (Pn = P, As)

Neue Arsenide mit ThCr2Si2- oder einer damit verwandten Struktur: Die Verbindungen ARh2As2 (A: Eu, Sr, Ba) und BaZn2As2 / New Arsenides with ThCr2Si2-type or Related Structures: The Compounds ARh2As2 (A: Eu, Sr, Ba) and BaZn2As2

Ternary BaAl4-type derivative structures

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Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

Magnetism and Negative Magnetoresistance of Two Magnetically Ordering, Rare-Earth-Containing Zintl phases with a New Structure Type: EuGa₂Pn₂ (Pn = P, As)

Neue Arsenide mit ThCr₂Si₂- oder einer damit verwandten Struktur: Die Verbindungen ARh₂As₂ (A: Eu, Sr, Ba) und BaZn₂As₂ / New Arsenides with ThCr₂Si₂-type or Related Structures: The Compounds ARh₂As₂ (A: Eu, Sr, Ba) and BaZn₂As₂

Ternary BaAl₄-type derivative structures