Superconducting properties of the oxygen-vacant iron oxyarsenide TbFeAsO1-x from underdoped to overdoped compositions

TL;DR

This study explores the superconducting properties of TbFeAsO1-x across a wide doping range, revealing a dome-shaped Tc dependence on lattice constants and the impact of oxygen vacancies on superconductivity.

Contribution

It demonstrates a high-pressure synthesis method to achieve broad doping in TbFeAsO1-x and analyzes the relationship between lattice parameters, oxygen vacancies, and Tc.

Findings

Tc reaches 44 K at optimal doping.

Tc vs. lattice constant follows a unique empirical curve.

Oxygen vacancies up to 0.3 are introduced in the compound.

Abstract

A wide-range doping was achieved by a high-pressure method for TbFeAsO1-x from "under doped" to "over doped" superconducting compositions throughout the optimized superconductivity (Tc of 44 K). Tc vs. lattice constant shows a dome-shaped feature, while Tc vs. the lattice constant likely follows a unique empirical curve over the doping range. The relatively large amount of oxygen vacancies up to 0.3 per the formula unit was introduced possibly because of the smaller replacement Tb than the other Ln (rare-earth element) in the LnFeAsO1-x system.