QuantAlpsAn ecosystem for quantum science & technologies :
From the philosopher to the industrial

Abstract: It has been claimed that graphite hosts superconductivity at room temperature, although all efforts to isolate it have been vain. Here, we report separation methods that use magnetic field gradients to sort the superconducting from normal grains out of industrial graphite powders. We have obtained a concentrate of above room temperature superconducting particles. Electrical resistance measurements on agglomerates of sorted grains of synthetic, natural and spectroscopically pure graphite all show transition temperatures up to Tc^{onset}~700 K with zero resistance up to ~500K. Magnetization measurements confirm these values through jumps at Tc in the zero field cooled curves, and by the occurrence of diamagnetic hysteretic cycles shrinking with temperature. Transmission electron microscope images yield a hint of the novel structure of these grains.