Al-27 and Sc-45 NMR Spectroscopy on ScT2Al and Sc(T0.5T '(0.5)) 2Al (T = T ' = Ni, Pd, Pt, Cu, Ag, Au) Heusler Phases and Superconductivity in Sc(Pd0.5Au0.5)(2)Al

作者：Be***orf Christopher; Niehaus Oliver; Eckert Hellmut; Janka Oliver^*

来源：Zeitschrift fur Anorganische und Allgemeine Chemie, 2015, 641(2): 168-175.

DOI：10.1002/zaac.201400509

• Intermetallics
• Crystal Structure
• Heusler
• Superconductivity
• Solid State NMR spectroscopy

The intermetallic Heusler compounds with ScT2Al and Sc(T0.5T0.5')(2)Al composition with T = T' = Ni, Pd, Pt, Cu, Ag, Au were synthesized from the elements by arc melting. They crystallize in the cubic MnCu2Al type structure, space group Fm (3) over barm. The unit cell parameters were determined by powder X-ray diffraction and the structure of Sc(Pd0.5Au0.5)(2)Al was refined on the basis of single-crystal X-ray diffraction. While the majority of the compounds show Pauliparamagnetism, ScAu2Al and the newly synthesized solid solution Sc(Pd0.5Au0.5)(2)Al exhibit superconductivity with transition temperatures of T-C = 4.4 K and T-C = 3.0(1) K, cly. The super-conduct- ing state of Sc(Pd0.5Au0.5)(2)Al was also investigated by electrical resistivity measurements. All the synthesized compounds were furthermore studied by Al-27 and Sc-45 MAS-NMR spectroscopy. The resonance shifts of the synthesized compounds were determined and in Sc(Pd1-xAux)(2)Al a linear relationship between the resonance shifts and the composition was found. Line broadening effects and enhanced quadrupolar interaction strengths observed in the mixed samples can he attributed to the effect of Pd/Au mixing on the 8c Wyckoff site. The NMR spectroscopic data give no clear evidence for or against Sc/Al site disordeiing.

• 出版日期2015-2