G. WENSKI's research while affiliated with University of Cologne and other places

Publications (14)

Article
Full-text available
Eu2Pt7AlP~3 (a = 4.046(1) Å, c = 26.850(2) Å, Z = 2) and some isotypic compounds were prepared by heating the elements. They crystallize tetragonally (I 4/m m m) in a new intergrowth structure where segments occur with atom arrangements as in the CaBe2Ge2⁻ and Cu3Au-type.
Article
The magnetic properties of the isotypic title phosphides (AlB2 type structure, P6m2, Z=1) and arsenides (AlB2 type related structure, P63/mmc) with SE: Sm, Gd, Tb, Tm, Yb, Lu are measured in the temp. range 4-300 K. At low temp. magnetic ordering phenomena are observed for GdPtAs, TbPtP (ferromagnetic below 48 and 50 K, resp.), SmPtAs, GdPtP (antif...
Article
Die magnetischen Eigenschaften von SEPtP und SEPtAs (SE = Sm, Gd, Tb, Tm, Yb, Lu) wurden im Temperaturbereich zwischen 4 und 300 K gemessen. Die Verbindungen kristallisieren im AlB2-Typ (Phosphide) bzw · einer Variante dieser Struktur (Arsenide). GdPtAs und TbPtP verhalten sich bei tiefen Temperaturen ferromagnetisch, SmPtAs und GdPtP antiferromagn...
Article
The four title compounds have been prepared by annealing mixtures of the elements (excess Sr and Ba, resp., 1000 °C, 2 weeks).
Article
Full-text available
The isotypic compounds SrPt 4 P 6 , SrPt 4 As 6 and BaPt 4 As 6 were found to crystallize with a Pyrite-type derivative structure (monoclinic, C2/c, Z = 4) in which one Sr or Ba atom per formula unit occupies the position of a P 2 or As 2 pair. BaPt 2 P 3 forms another Pyrite-type related structure (monoclinic, P2 1 /c, Z = 4) built up by Ba 2 Pt a...
Article
CaPtP und CaPtAs kristallisieren in neuen ternären AlB2-Varianten: Die Struktur von CaPtP ist aus verzerrten PtP-Sechsecknetzen aufgebaut (Pmc21; a = 434,4 pm, b = 831,1 pm, c = 651,9 pm), für CaPtAs ermittelten wir eine Atomanordnung, die sich aus Strukturelementen des AlB2- und des ThSi2-Typs zusammensetzt (I41md; a = 418,3 pm, c = 4371,1 pm). Eu...
Article
The title compounds are prepared by heating (z 1000°C) mixtures of the elements in corundum crucibles in Ar atmosphere.
Article
BaPtP und BaPtAs kristallisieren in ternären Varianten der SrSi2-Struktur, in denen die Si-Positionen auf unterschiedliche Weise geordnet von Pt und P(As) besetzt sind (P213; BaPtP: a = 653,3 pm, BaPtAs: a = 671,6 pm). Für die übrigen im Titel angegebenen Verbindungen fanden wir den AlB2-Typ mit statistischer (P6/mmm) oder geordneter (P6m2) Verteil...
Article
Several new compounds REPtX (RE = Y, rare earth element except Eu; X = P, As, Sb) have been synthesized and examined by X ray methods. The phosphides crystallize with AlB2-type structure. The arsenides possess a new AlB2-type derivative structure with puckered PtAs layers and cREPtAs ≈ 4cAIB2. For the compounds REPtSb we found a modified CaIn2-type...
Article
Full-text available
Compounds ARu2P(As)2 (A = Ca, Sr. Ba. Eu) were found to have the ThCr2Si2-type structure (14/mmm). Single crystals of CaRu2P2 (a = 404.6 pm, c = 977.1 pm) and EuRu2P2 (a = 402.9 pm, c = 1077.2 pm) were obtained using tin as a flux. In the case of the Pt compounds, single crystals could be isolated from powder samples. Ca(Eu)Pt2P2-x crystallizes iso...

Citations

... The ordered honeycomb network structure therefore appears to be favourable for the occurrence of superconductivity. In this paper, we report the discovery of superconductivity in CaPtAs with T c = 1.47 K, which adopts a noncentrosymmetric tetragonal structure consisting of twisted three-dimensional (3D) honeycombs of Pt-As along the c-axis [38]. ...
... Unfortunately, we were not able to do the structure determination for these compounds on single crystals at the time. Some preliminary results about the structure of Dy 12 Ni 30 As 21 and Tb 12 Ni 30 As 21 have been reported in literature [15], and finally the crystal structure of Dy 12 Ni 30 As 31 has been proposed in literature [16] as a (La, Ce) 12 Rh 30 P 21 -type related structure. ...
... Variations of / 0 and / 0 as functions of pressure are illustrated in figure 3, where ( ) is the lattice parameter (unit cell volume) at the considered pressure and 0 ( 0 ) is the corresponding value at zero pressure. The obtained results for / 0 and / 0 in the considered range of pressure are well fitted to a third-order polynomials: Ref [16], Ref [28], f [29], Ref [14], Ref [15], Ref [30], Ref [31], ℎ Ref [32]. ...
... Along these lines, it is interesting to note that in LaPtSb, the buckling is largely manifested in out-of-plane shifts of the Pt atoms, minimizing La-Sb collisions, while in LaAuGe, the smaller Ge atoms show greater displacement. These results also correlate with observations described in the literature for other AlB 2 -type variants, [38][39][40] where the degree of buckling in the crystal structures is often attributed to the size of the stuffing cation A. As the radius of the stuffing cation increases, c increases and interactions between the layers are reduced. With increasing atomic radii, the structures transition from a stuffed wurtzite network (LiGaGe-type) to stuffed graphite sheets (ZrBeSi-type). ...
... CaPtAs is superconducting below T c = 1.47 K 146 , and has a noncentrosymmetric tetragonal structure consisting of a three-dimensional hexagonal network of Pt-As atoms, with the same chiral space group (I4 1 md) as a number of equiatomic ternary SC's RT X (R=La or Th, T =transition metal, X=Si, Ge, As or P) [147][148][149][150][151][152][153][154] . The structure of CaPtAs however is different from the LaPtSitype structure of the latter compounds, having a greatly elongated c-axis which is about three times longer 155 . ...
... SrPtAs crystallizes in the hexagonal non-symmorphic space group P 6 3 /mmc (No. 194) [9], wherein Pt and As form a honeycomb lattice. This is in contrast to other pnictide superconductors which form with a square lattice such as LaFePO [10], LaFeAsO [11], LiFeAs [12], NaFeAs [13] and ThCr 2 Si 2 -type structures like (Ba 1−x K x )Fe 2 As 2 [14]. ...