High-pressure synthesis and magnetic characterization of quadruple perovskites SmA′3Co4O12 (A' = Cu, Mn)

In this study, two novel quadruple perovskite compounds SmA′3Co4O12 (A' = Cu, Mn) were synthesized using a high-pressure synthesis method. Structural analysis of the perovskites using synchrotron X-ray powder diffraction revealed that both SmCu3Co4O12 and SmMn3Co4O12 have cubic Im 3¯ structure. In the temperature range of 2–300 K, SmCu3Co4O12 did not exhibit a magnetic phase transition, whereas SmMn3Co4O12 exhibited a paramagnetic to ferrimagnetic phase transition at ∼90 K. A comparison of structural information, X-ray absorption near edge structure, and magnetic properties revealed that the low-spin state (S = 0) characterizes the spin state of Co3+ when the A′ site is occupied by Cu3+. However, when the A′ site is occupied by Mn3+, the Co3+ spin state is in a high-spin state (S = 2), indicating that a long-range magnetic phase transition occurs owing to the magnetic interaction between the Mn and Co ions.