  We report the experimental discovery of superconductivity with critical
temperature Tc above 70 K in zirconium polyhydrides, the record high so far for
3d transition metal hydrides. The superconducting zirconium polyhydrides are
synthesized at the extreme conditions above 200 GPa & 2000 K by using diamond
anvil cell combined with in-situ laser heating. Superconductivity was observed
in the samples maintained at the same pressure upon quenched from heating.
