Superconductivity in the Th_0.93Zr_0.07B₁₂ compound with UB₁₂ prototype structure

In this work, we report superconductivity at 5.5 K in the new pseudo-ternary Th_0.93Zr_0.07B₁₂ 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 Th_0.93Zr_0.07B₁₂ 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 μ₀H_c1(0)=6 mT and μ₀H_c2(0)=98 mT and allow us to estimate the coherence length ξ_o∼57.9 nm and the penetration depth λ_L∼234 nm at zero kelvin.