No evidence of superconductivity in a compressed sample prepared from lutetium foil and H2/N2 gas mixture

A material described as lutetium-hydrogen-nitrogen (Lu-H-N in short) was recently claimed to have "near-ambient superconductivity" [Dasenbrock-Gammon et al., Nature 615, 244-250 (2023)]. If this result could be reproduced by other teams, it would be a major scientific breakthrough. Here, we report our results of transport and structure measurements on a material prepared using the same method as reported by Dasenbrock-Gammon et al. Our x-ray diffraction measurements indicate that the obtained sample contains three substances: the face-centered-cubic (FCC)-1 phase (Fm-3m) with lattice parameter a = 5.03 angstrom, the FCC-2 phase (Fm-3m) with a lattice parameter a = 4.755 angstrom, and Lu metal. The two FCC phases are identical to the those reported in the so-called near-ambient superconductor. However, we find from our resistance measurements in the temperature range from 300 K down to 4 K and the pressure range 0.9-3.4 GPa and our magnetic susceptibility measurements in the pressure range 0.8-3.3 GPa and the temperature range down to 100 K that the samples show no evidence of superconductivity. We also use a laser heating technique to heat a sample to 1800 degrees C and find no superconductivity in the produced dark blue material below 6.5 GPa. In addition, both samples remain dark blue in color in the pressure range investigated. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).