Fig. 4. Magneto-transport properties of the infinite-layer Pr_0.82Sr_0.18NiO₂ thin films and superconducting properties in nickelate thin films.

a Temperature dependence of the resistivity with magnetic fields up to 8.5 T at 12.1 GPa. b Temperature dependences of the upper critical field μ₀H_c2 at different pressures, where μ₀H_c2 values are determined by using the criteria of 90% ρ_n. The broken lines represent the Ginzburg–Landau (G-L) fitting curves and the μ₀H_c2^orb(0) calculated from WHH model at 0 GPa is indicated. c Pressure dependence of the zero-temperature upper critical field μ₀H_c2(0) obtained from the empirical G-L fitting and the WHH model, and the normalized slope –(1/T_c)[dμ₀H_c2/dT]|_Tc. d c-axis dependence of T_c in the series of infinite nickelates superconducting thin films. The error bars of the upper critical field in c are obtained from the fitting results.