12255-80-0Relevant articles and documents
Ni11as8 single-crystalline nanosheets via hydrothermal redox route
Wei, Shuo,Lu, Jun,Yu, Weichao,Zhang, Houbo,Qian, Yitai
, p. 3844 - 3849 (2005)
Ni11As8 crystallites 23-nm thick and 250-700-nm wide in lateral dimension were prepared in alkaline hydrothermal condition. Transmission electron microscope (TEM) images and selected area electron diffraction (SAED) analyses showed that the as-prepared Ni11As 8 was single-crystalline nanosheets of [331] orientation. The Ni 11As8 exhibited an optical absorption onset of 3.00 eV in the visible spectral regime. Its magnetic measurement indicated a weak magnetic hysteresis and unsaturation magnetization with a magnetic susceptibility of 1.37 × 10-44 cm3/g (at 15 kOe) at room temperature, the origin of which was discussed and assigned to the effect of surface species containing Ni ions. The extended Hueckel tight-binding calculation revealed that bulk Ni11As8 has a 3d-localized narrow band below Fermi level and complicated band structure with small band gap in the first Brillouin zone, which supply clues to explain the observed optical and magnetic properties. The formation mechanism of Ni11As8 was studied and attributed to an alkaline hydrothermal redox route on the basis of the Marsh reaction.
Exotic Compositional Ordering in Manganese–Nickel–Arsenic (Mn-Ni-As) Intermetallics
Fjellv?g, ?ystein Slagtern,Fjellv?g, Helmer,Gonano, Bruno,Pelloquin, Denis,Saha, Dipankar,Steciuk, Gwladys
, p. 22382 - 22387 (2020)
In this work we benefited from recent advances in tools for crystal-structure analysis that enabled us to describe an exotic nanoscale phenomenon in structural chemistry. The Mn0.60Ni0.40As sample of the Mn1?xNixAs solid solution, exhibits an incommensurate compositional modulation intimately coupled with positional modulations. The average structure is of the simple NiAs type, but in contrast to a normal solid solution, we observe that manganese and nickel segregate periodically at the nano-level into ordered MnAs and NiAs layers with thickness of 2–4 face-shared octahedra. The detailed description was obtained by combination of 3D electron diffraction, scanning transmission electron microscopy, and neutron diffraction. The distribution of the manganese and nickel layers is perfectly described by a modulation vector q=0.360(3) c*. Displacive modulations are observed for all elements as a consequence of the occupational modulation, and as a means to achieve acceptable Ni–As and Mn–As distances. This modulated evolution of magnetic MnAs and non-magnetic NiAs-layers with periodicity at approximately 10 ? level, may provide an avenue for spintronics.
Structure and Transport Properties in Itinerant Antiferromagnet RE2(Ni1-xCu x)5As3O2 (RE = Ce, Sm)
Chen, Xu,Guo, Jian-Gang,Gong, Chunsheng,Cheng, Erjian,Song, Yanpeng,Ying, Tianping,Deng, Jun,Li, Shiyan,Chen, Xiaolong
, p. 2770 - 2776 (2019/02/28)
We report the crystal structure and physical properties of two Ni5As3-based compounds RE2Ni5As3O2 (RE = Ce, Sm). The former exhibits structural phase transition from tetragonal (space group I4/mmm, 139) to orthorhombic (space group Immm, 71) symmetry at 230 K, while the latter undergoes a charge-density-wave-like structural distortion with abrupt change of Ni-As bond length. Both compounds show antiferromagnetic transitions due to RE3+ ions ordering at 4.4 and 3.4 K, accompanying with the large enhancement of Sommerfeld coefficients comparing to the nonmagnetic La analogue. Although the Cu substitution for Ni induces structural anomalies and suppression of structural transition like the behaviors in La/Pr/Nd analogues, the superconductivity is not observed in both Cu-doped RE2Ni5As3O2 (RE = Ce, Sm) above 0.25 K. Our structural refinements reveal that the lacking of superconductivity in RE2(Ni1-xCux)5As3O2 might relate to the anomalous increase of As height, h1.
