Superconductors comprising 5d transition metals of Ir and Pt have been widely explored because they have the potential of unique superconductivity caused by the strong spin-orbit interaction (SOI). We successfully synthesized BaIr₂, the last Laves phase remaining unsynthesized in the MgCu₂-type AM₂ (A = Ca, Sr, Ba; M = Rh, Pd, Ir, Pt). BaIr₂ was crystallized at 925 °C under a pressure of 3.3 GPa via a solid-state reaction between Ba and Ir powders; it was found to have the longest a-lattice constant of 8.038 (1) Å among AM₂. BaIr₂ exhibited bulk superconductivity at a transition temperature (T_c) of ∼2.7 K BaIr₂ was found to have a type-II superconductor with an upper critical field of 67.7 kOe, which was above the Pauli paramagnetic limit (∼50 kOe). The electron–phonon coupling constant and normalized specific heat jump were measured to be 0.63 and 1.2, respectively, indicating that BaIr₂ is a weak-coupling superconductor. The electronic-structure calculations for BaIr₂ revealed that the Ir-5d states are dominant at the Fermi energy (E_F) and the density of states at the E_F is strongly affected by SOI as in the case of CaIr₂ and SrIr₂.

包含 Ir 和 Pt 的 5 d过渡金属的超导体已被广泛探索，因为它们具有由强自旋轨道相互作用 (SOI) 引起的独特超导性的潜力。我们成功合成了 BaIr ₂，最后一个 Laves 相在 MgCu ₂型AM ₂ ( A  = Ca, Sr, Ba; M  = Rh, Pd, Ir, Pt)中仍未合成。BaIr ₂通过 Ba 和 Ir 粉末之间的固态反应在 3.3 GPa 压力下在 925 °C 下结晶；在AM ₂中，它被发现具有最长的α-晶格常数8.038 (1) Å 。巴尔₂在约 2.7 K 的转变温度 ( T _c )下表现出体超导性BaIr ₂被发现具有上临界场为 67.7 kOe 的 II 型超导体，高于 Pauli 顺磁极限 (约 50 kOe)。测得的电子-声子耦合常数和归一化比热跃变分别为 0.63 和 1.2，表明 BaIr ₂是一种弱耦合超导体。_{BaIr 2}的电子结构计算表明， Ir- 5d态在费米能量 ( E _{F ) 处占主导地位，并且}E _F处的态密度受到 SOI 的强烈影响，就像 CaIr _{2的情况一样}和 SrIr ₂。