Discovery of Li2(Pd,Pt)3B superconductors

TL;DR

This study investigates the superconducting properties of Li2(Pd,Pt)3B compounds, exploring how composition and processing affect critical temperature, and identifies conditions that optimize superconductivity.

Contribution

It provides new experimental data on how precursor composition, lithium content, and annealing influence Tc in Li2(Pd,Pt)3B superconductors.

Findings

Optimal Pd:B ratio is close to 3:1 for maximum Tc.

Post-annealing at 560°C enhances Tc up to 8.4K.

Re3B compound shows superconductivity among other compositions.

Abstract

Critical temperature Tc of the Li2(Pd1-xPtx)3B was reported to be 7-8K for x=0 and 2.2-2.8K for x=1. In this article we present our preliminary results on behavior of magnetization-temperature curves with starting composition of Pd-B precursor, y-Li concentration in LiyPd3B and post-annealing of the Pd-end compound. Results suggest that to maximize Tc ratio Pd:B should be close to 3:1, while y-Li has to be optimum. The lowest Tc for LiyPd3B was 4.4-4.6K, while post-annealings at 560 deg. C allowed enhancement of Tc up to 8.2-8.4K. Compositions Li2Z3B with Z=Ni, Ru, Rh, Re, Ag are not superconducting down to 1.8K. Exception is composition with Re showing superconductivity due to Re3B compound. All samples were prepared by arc melting.