We present detailed studies of the superconductivity in high-pressure ${\mathrm{H}}_3\mathrm{S}$. X-ray diffraction measurements show that cubic $Im\overline{3}m {\mathrm{H}}_3\mathrm{S}$ was synthesized from elemental sulfur and hydrogen donor ammonia borane (${\mathrm{NH}}_3{\mathrm{BH}}_3$). Our electrical transport measurements confirm superconductivity with a transition temperature $T_c=197\mathrm{K}$ at $153\mathrm{GPa}$. From the analysis of both the normal-state resistivity and the slope of the critical field, we conclude that the superconductivity is described by clean-limit behavior. A significant broadening of the resistive transition in finite magnetic field is found, as expected for superconductors. We identify a linear temperature-over-field scaling of the resistance at the superconducting transition which is not described by existing theories.

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• Superconductivity
• Hydrides
• Density functional theory
• Pressure techniques
• Resistivity measurements
• X-ray powder diffraction