Single crystals growth and physical properties characterization of NbSe2 superconductor

Abstract

In this chapter, a brief description of the current research on different superconducting materials is demonstrated. It includes the discoveries from low transition temperature superconductors to high transition temperature superconductors, their properties and the applications associated with them. Also, the previous and the ongoing researches on Niobium Diselenide (NbSe2) superconductor are highlighted. In this section all the significant characteristics of NbSe2 single crystals have been discussed elaborately extracting from different physical properties measurements. Finally, this thesis covers a precise overview of the diverse applications of NbSe2 and the objectives and outline of the thesis work. Succeeding the discovery of superconductivity in mercury at 4 K by Kamerlingth Onnes in 1911, various new superconducting materials have been explored, which led to an incredible growth of higher transition temperature (Tc) superconductors over the decades. The discovery of high Tc superconductor enlightened the way for applications which involves only liquid N2 cooling (77 K), rather than liquid helium. Till now, there is no final agreement of the mechanism causing the high Tc in these materials. However, the most important difference in physical properties between a high Tc and conventional BCS type superconductors is the presence of extreme anisotropy, which is caused by its layered structure, and from the extremely short coherence length. The layered structured materials show highly anisotropic magnetic behaviour, and in extreme cases the two-dimensional behaviour that are resulting from the decoupled superconducting film planes. From this starting point of view, we will focus on the superconducting properties of the anisotropic, layered low Tc superconductors.NbSe2 is one of the extremely debatable quasi two-dimensional transition metal dichalcogenides (TMDCs) that displays the metallic character at room temperature, but undergoes to a superconducting state under a certain temperature ~ 7.2 K. Due to the layered structure, NbSe2 manifests a strong anisotropy associated with its electronic, transport and magnetic properties.