Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAsO_{1-x}F_x$

TL;DR

This paper reports the discovery of bulk superconductivity at 43 K in samarium-arsenide oxides, marking the first non-copper oxide superconductor with a transition temperature exceeding 40 K, challenging existing theories.

Contribution

The study introduces a new non-copper oxide superconductor, $SmFeAsO_{1-x}F_x$, with a $T_c$ above 40 K, expanding the landscape of high-$T_c$ materials.

Findings

Superconductivity at 43 K confirmed in $SmFeAsO_{1-x}F_x$

First non-copper oxide superconductor with $T_c$ > 40 K

Evidence suggests unconventional superconductivity

Abstract

Since the discovery of high-transition temperature ($T_c$) superconductivity in layered copper oxides, extensive efforts have been devoted to explore the higher $T_c$ superconductivity. However, the $T_c$ higher than 40 K can be obtained only in the copper oxide superconductors so far. The highest reported value of $T_c$ for non-copper-oxide bulk superconductivity is 39 K in $MgB_2$.\cite{jun} The $T_c$ of about 40 K is close to or above the theoretical value predicted from BCS theory.\cite{mcmillan} Therefore, it is very significant to search for non-copper oxide superconductor with the transition temperature higher than 40 K to understand the mechanism of high-$T_c$ superconductivity. Here we report the discovery of bulk superconductivity in samarium-arsenide oxides $SmFeAsO_{1-x}F_x$ with ZrCuAiAs type structure. Resistivity and magnetization measurements show strong evidences for transition temperature as high as 43 K. $SmFeAsO_{1-x}F_x$ is the first non-copper oxide superconductor with $T_c$ higher than 40 K. The $T_c$ higher than 40 K may be a strong argument to consider $SmFeAsO_{1-x}F_x$ as an unconventional superconductor.