Superconductivity in the Th0.93Zr0.07B12 compound with UB12 prototype structure

In this work, we report superconductivity at 5.5 K in the new pseudo-ternary Th0.93Zr0.07B12 compound. We show clearly evidence that appropriate amounts of Zr substitution at the Th site induce the stabilization of the UB12 prototype structure at ambient pressure. The superconducting bulk properties of Th0.93Zr0.07B12 are confirmed by means of magnetization, electronic transport properties and specific heat measurements. The H-T phase diagrams based on magnetization and magnetoresistance measurements yield μ0Hc1(0)=6 mT and μ0Hc2(0)=98 mT and allow us to estimate the coherence length ξo∼57.9 nm and the penetration depth λL∼234 nm at zero kelvin