Raman scattering, X-ray photoemission spectra and superconductivity of a tiny Ag diffusion to MgCNi3

TL;DR

This study investigates how tiny silver diffusion affects the structure, surface properties, and superconductivity of MgCNi3, revealing changes in Raman spectra and a lowered transition temperature explained by BCS theory.

Contribution

It provides new insights into the effects of silver substitution and vacancy incorporation on MgCNi3's properties and superconducting behavior.

Findings

Ag substitutes for Ni sites and occupies vacancies in MgCNi3.

Ag diffusion introduces a unique Raman peak at 842.1 cm-1.

Superconducting transition temperature decreases to 6.6 K, explained by BCS phonon mechanism.

Abstract

The tiny Ag diffusion to MgCNi3 has been prepared by solid states reaction. Its structure was characterized by X-ray diffractometer (XRD). The results show that a small mount of Ag substitute for Ni sites, and much of Ag are in vacancy sites of the MgCNi3. We have further studied the surface properties of Ag-MgCNi3 using Raman scattering spectra, and X-ray photoemission spectra (XPS). Raman spectroscopy shows that the Ag-MgCNi3 has a special Raman peak around 842.1 cm-1 compared to that of C. The superconductor transition temperature (about 6.6 K) of Ag-MgCNi3 was lower than that of pure MgCNi3. It was interpreted properly by the conventional BCS phonon mechanism.