Extended Data Fig. 3: Resistance of La3Ni2O7−δ single crystal samples under pressure.
From: High-temperature superconductivity with zero resistance and strange-metal behaviour in La3Ni2O7−δ
We measured the R(T) curves of seven La3Ni2O7−δ single crystal samples under pressure. a-d, Four samples exhibited zero resistance at high pressures, and energy-dispersive x-ray analysis (EDX) measurements (Extended Data Fig. 4) show that three of these samples are more homogeneous and close to the stoichiometric composition (S1-1, S1-2, S1-3), while EDX of sample S2-1 was not measured as it broke upon releasing the pressure. For sample S1-3, in order to measure the Hall resistivity at high pressures (Extended Data Fig. 8), we used a 500-μm-diameter culet, which results in a more uneven pressure distribution near its maximum pressure of 20 GPa, leading to a broader superconducting transition at 18.9 GPa for this sample. e-g, The three samples (S2-2, S2-3, S2-4) with compositions far from 3:2:7 with large δ did not show zero resistance.
