Carbon isotope effect in superconducting MgCNi_3

TL;DR

This study investigates the carbon isotope effect on the superconducting transition temperature in MgCNi_3, demonstrating that carbon phonons significantly influence its superconductivity.

Contribution

It provides experimental evidence of the carbon isotope effect in MgCNi_3, highlighting the role of carbon phonons in its superconductivity.

Findings

Carbon isotope substitution reduces T_c from 7.12 K to 6.82 K

The isotope effect coefficient is approximately 0.54

Results suggest phonons involving carbon are critical for superconductivity

Abstract

The effect of Carbon isotope substitution on T_c in the intermetallic perovskite superconductor MgCNi_3 is reported. Four independent groups of samples were synthesized and characterized. The average T_c for the Carbon-12 samples was found to be 7.12(2) K and the average T_c for the Carbon-13 samples was found to be 6.82(2) K. The resulting carbon isotope effect coefficient is alfa_C = 0.54(3). This indicates that carbon-based phonons play a critical role in the presence of superconductivity in this compound.