Superconductivity in the Zr-Ir system

Superconductivity of the Zr-Ir system alloys within the Ir concentration range 10 to 75 atomic per cents was studied by the induction method. The superconducting properties of Zr3Ir (Tsub(k) = 2.1 deg K) and Zr2Ir (Tsub(k) = 7.3 deg K) compounds were discovered. It was established that superconductivity is displayed by the alloy which has been cast and annealed at 1400 deg C and which corresponds to stoichiometry of ZrIr compound. A conclusion on possible polymorphism of the given compound with superconducting high-temperature modification was made. It is established that the phase based on Zr5Ir3 and ZrIr3 do not display superconductivity at temperatures higher than 1.85 deg K. The superconducting properties of ZrIr2 (Tsub(k) = 4.03 deg K) and of the alloy containing 10 atomic per cent Ir (Tsub(k) = 5.5 deg K) have been confirmed. The superconductivity of the Zr-Ir system within a wide concentration range of the alloying elements in the cast, quenched and annealed states was studied. It was established that the superconductivity is displayed at temperatures above 1.85 deg C by almost all investigated alloys, except annealed alloys containing 37.5, 50.75 atomic per cent Ir. The maximum critical temperature of 7.3 deg K is specific to the alloy which corresponds to stoichiometry of Zr2Ir compound