Bindungsverhältnisse und magnetische Eigenschaften ternärer Arsenide ET₂As₂ / Bonding and Magnetic Properties in Ternary Arsenides ET₂As₂

Abstract

<jats:title>Abstract</jats:title><jats:p> The interatomic distances of ternary arsenides ET<jats:sub>2</jats:sub>As<jats:sub>2</jats:sub> with ThCr<jats:sub>2</jats:sub>Si<jats:sub>2</jats:sub>-structure were determined by X-ray powder methods (E = Ca, Sr, Ba; T = Cr, Fe, Co, Ni, Cu). The phases were found to behave according to the Zintl-Klemm-Busmann concept. Magnetic susceptibilities were measured.</jats:p>

Transport properties and superconductivity in Ba 1-x M x Fe 2 As 2 (M=La and K) with double FeAs layers

“…Figure 2 shows temperature dependence of resistivity for the samples BaF e 2 As 2 , Ba 0.85 La 0.15 F e 2 As 2 , Ba 0.6 K 0.4 F e 2 As 2 and Ba 0.5 K 0.5 OF e 2 As 2 . The resistivity of BaF e 2 As 2 shows a linear temperature dependence above a characteristic temperature of about 140 K, and show a steeply decrease with decreasing temperature below 140 K. These results are consistent with previous report [1], and the characteristic temperature is ascribed to antiferromagnetic phase transition [13]. As reported by Rotter et al, a superconducting transition at about 38 K is observed in resistivity in K-doping sample Ba 0.6 K 0.4 F e 2 As 2 .…”

Crystal growth and physical properties of SrCu2As2, SrCu2SbAnand1, Perera2, Pandey3 et al. 2012Phys. Rev. B

“…To our knowledge, detailed investigations of the physical properties of these compounds have not been previously carried out. Pfisterer and Nagorsen reported in 1983 that the χ of a polycrystalline sample of SrCu 2 As 2 was diamagnetic and nearly independent of T from 80 to 400 K. 33 Our measurements confirm the above theoretical prediction 29 that SrCu 2 As 2 is an sp-band metal and we find that it also applies to the other three compounds studied here as well. Thus the Cu ions have a formal oxidation state of Cu +1 with a nonmagnetic 3d 10 electronic configuration.…”

“…5,33,40,41,54,55, The d X−X and the c/a ratio for X = As and P are plotted versus M in Figs For SrCu 2 As 2 , our value d As−As = 2.470(2)Å is close to the As-As covalent bond distance 2.38(8)Å, which confirms that the formal oxidation states of Cu and As atoms in this compound are Cu +1 and As −2 as discussed Table VIII. above. The +1 oxidation state of Cu is consistent with our ρ(T ), C p (T ) and χ(T ) measurements of SrCu 2 As 2 as also previously discussed.…”

“…6 is significantly more diamagnetic (negative) than the T -independent value between 80 and 400 K of χ = −5.4 × 10 −5 cm 3 /mol reported previously for a polycrystalline sample. 33 This difference may be due to a saturation magnetization of ferromagnetic (FM) impurities in the latter sample that was incompletely corrected for.…”

“…To investigate these issues, we synthesized single crystals of the previously known [30][31][32][33] Cu-based compounds SrCu 2 As 2 , SrCu 2 Sb 2 and BaCu 2 Sb 2 and measured their structural, magnetic, thermal and electronic transport properties, and report here our results. We also synthesized and studied crystals of SrCu 2 (As 0.84 Sb 0.16 ) 2 .…”