Non-bulk Superconductivity in Pr$_4$Ni$_3$O$_{10}$ Single Crystals Under Pressure

TL;DR

This study reports pressure-induced signatures of superconductivity in Pr4Ni3O10 single crystals, with a maximum onset temperature of 31 K, but no true zero resistance, indicating a non-bulk, minority superconducting phase.

Contribution

It demonstrates that Pr4Ni3O10 crystals contain a minority superconducting phase induced by pressure, highlighting inhomogeneities and non-bulk nature of the observed superconductivity.

Findings

Superconductivity signatures observed up to 73 GPa pressure.

Superconducting volume fraction estimated around 10%.

Sample-to-sample and contact configuration variations affect Tc.

Abstract

Magneto-transport measurements of Pr$_4$Ni$_3$O$_{10}$ single crystals performed under externally applied pressures up to 73 GPa in diamond anvil cells with either KBr or Nujol oil as pressure media yield signatures of superconductivity with a maximum onset temperature of approximately 31 K. True zero resistance was not observed, consistent with a non-percolating superconducting volume fraction. Magnetization measurements provided corroborating evidence of superconductivity, with a pressure-dependent diamagnetic signal occurring below the onset temperature, and an estimate from the absolute value of the susceptibility suggests a superconducting volume fraction on the order of 10%. We observe sample-to-sample variations in the magnitude and pressure dependence of Tc as well as a dependence on the configuration of electrical contacts on a given sample. Possible causes of this behavior may be significant inhomogeneities in the pressure and/or damage to the samples induced by the pressure media as well as inhomogeneities in the crystals themselves. The results imply that our as-grown Pr$_4$Ni$_3$O$_{10}$ single crystals are not bulk superconductors but that there is a minority structure present within the crystals that is indeed superconducting.