Structural Phase Transition and Interesting Magnetism of Ni Intercalated NbS2 (0 ≤ x ≤ 0.5)

Abstract

Layered materials, particularly, layered transition metal dichalcogenides (TMDs) have generated huge research interest due to their exotic two-dimensional physical properties and structural diversity. The layered TMDs have hexagonal layered structure in which a layer of metal atoms covalently bonded to two layers of chalcogens (X-M-X, X = S, Se, and Te, M = Any Metal atom). In this work, we intercalated Ni in the NbS2 system (0 ≤ x ≤ 0.5) at 1000 °C, in which guest species Ni accommodates octahedral vacancies of the van der Wall gap. Intercalation on NbS2 noticed significant changes in the structural, magnetic properties compare with pristine NbS2. The 2H phase is obtained in the composition range of (0.15 ≤ x ≤ 0.5), while pristine NbS2 forming 3R phase. From NixNbS2 magnetic studies with different intercalant compositions noticed peculiar types of magnetic behaviour. Moreover, NixNbS2 (x = 0.1) exhibited superconductivity with Tc 7.9 K which is higher than reported pristine NbS2 Tc 5.7 K, while Ni0.2NbS2 showing the Anti-Ferromagnetic behaviour with transition temperature of 78.5 K (Neel temperature). From Raman spectroscopy studies detected new stretching vibration peak of Ni-S at 284.6 cm−1 which means Ni strongly interacted with the host NbS2 layer. XPS studies confirmed corresponding elements oxidation states.