Nickel-based layered superconductor, LaNiOAs

Abstract

Rietveld analysis of the powder X-ray diffraction of a new layered oxyarsenide, LaNiOAs, which was synthesized by solid-state reactions, revealed that LaNiOAs belongs to the tetragonal ZrCuSiAs-type structure (P4/nmm) and is composed of alternating stacks of La-O and Ni-As layers. The electrical and magnetic measurements demonstrated that LaNiOAs exhibits a superconducting transition at 2.4 K, and above this, LaNiOAs shows metallic conduction and Pauli paramagnetism. The diamagnetic susceptibility measured at 1.8 K corresponded to ~20% of perfect diamagnetic susceptibility, substantiating that LaNiOAs is a bulk superconductor.

Electron–phonon properties of pnictide superconductors

“…The resulting Fermi surface comprises two cylindrical hole pockets centered at the Γ point, and a doubly-degenerate electron pocket centered at the M point; these sheets have a Table 1: Structural data of LaOFeAs and LaONiAs from experiment (Refs. [20] and [12]), and DFT (Ref. [10] and this work).…”

“…We also decided to include new results for the Ni compound, LaONiAs, which is the only other member of the LaOMAs family (M=Mn,Fe,Co,Ni,Cu,Zn) [11] showing superconductivity, albeit with a much lower T c ≈ 2.4-3.8 K [12,13,14].…”

Insulator-to-metal transition and large thermoelectric effect in La 1−x Sr x MnAsO

“…LaMnAsO (LMAO) is an antiferromagnetic (AFM) semiconductor/insulator with pretty high Neel temperature of 317 K; 10,11 LaFeAsO is an AFM 12 semi-metal 13 , serving as mother compound for Fe-based superconductors; LaCoAsO is an itinerant ferromagnet with Curie temperature of 66 K; 14 and LaNiAsO is a BCS-type superconductor with transition temperature T c ∼3 K. 15,16 Fang and co-workers 17 performed first-principles calculations for the series of 1111 compounds. They were able to predict the AFM insulating ground state for LMAO, and the moment of Mn ions was calculated to be 3.1 µ B , consistent with the later experimental value of 3.34(2) µ B at 2 K.…”

Electronic structure of Fe-based superconductors

“…[9,10,11] In addition, superconductivity has been found in the corresponding pure Ni based compounds, both the oxypnictides and in the ThCr 2 Si 2 structure. [12,13,14,15] However, the superconductivity in these compounds can be understood as ordinary electron-phonon superconductivity, [16,17,18] in contrast to the Fe-based materials, which cannot be understood in this way. [19,20] The related Co compounds are not superconducting and are either ferromagnetic or near ferromagnetism.…”