Cryogenic magnetocaloric properties of zinc-based perovskite Nd2ZnZn(Zn2Sb2)O12 with A-site columnar-type and B-site rock-salt-type orders

Properties of perovskite-structure materials are highly sensitive to the degree of cation (and anion) orders. Therefore, it is important to know strategies of controlling such orders. Here we report a high-pressure, high-temperature synthesis of the first example of a Zn-based Nd₂ZnZn(Zn₂Sb₂)O₁₂ perovskite, with a full order of Nd³⁺ and Zn²⁺ at A sites in the columnar-type manner (with Zn²⁺ at square-planar and tetrahedral sites) and with a full order of Zn²⁺ and Sb⁵⁺ at octahedral B sites in the rock-salt-type manner. The sample was prepared at a moderate pressure of 6 GPa, which is much smaller than the pressure range (14–18 GPa) proposed in the literature for such perovskites. The sample exhibited paramagnetic behavior down to 1.8 K. On the other hand, it showed strong magnetic-field dependence of specific heat, indicating a notable magnetocaloric effect at low temperatures, which was further quantified using both specific heat and isothermal magnetization measurements. Considering the structural features, this compound could be an archetype for exploring rare-earth magnetism in a one-dimensional lattice.