Upper Critical Field of a Novel 18-K Superconductive Phase in Metastable Yttrium Sesquicarbide Prepared Using High Pressure Technique

TL;DR

This study successfully prepared and characterized a metastable yttrium sesquicarbide phase with an 18 K superconducting transition, revealing high critical fields comparable to A15 compounds, using high-pressure synthesis.

Contribution

The paper reports the reproducible synthesis and transport measurement of a new 18 K superconducting phase in yttrium sesquicarbide, demonstrating its high critical field properties.

Findings

Superconducting transition temperature (Tc) of 18 K confirmed.

Upper critical field (Bc2) exceeds 30 T at 0 K.

High Tc and Bc2 comparable to A15 superconductors.

Abstract

The metastable phase of an yttrium sesquicarbide compound, which was vary recently reported as a new superconductive phase with a Tc value of 18 K, was prepared under high pressure from the nominal composition of Y2C3 and Y2C2.9B0.1 in order to investigate this phase. We have succeeded in reproduction, and in the transport measurement for this 18-K phase. It is considered that the reason for the higher Tc value than the 11.5 K reported previously is not the small amount of B as the impurity element from the BN crucible. The Bc2 value at 0 K estimated from the resistivity data for the 18-K phase seems to be over 30 T. It means that the Tc and Bc2 values of the 18-K phase are as high as those of the general A15 compounds.