High-field magnetization study of spin-chain compounds Ca3Co2−xMnxO6

High-field magnetization measurements of spin-chain compounds Ca3Co2−xMnxO6 reveal the presence of two metamagnetic transitions within the Mn composition range of x=1.0-0.8. These transitions are associated with spin-configuration changes from zero-field ↑↑↓↓ to ↑↑↓↑, and finally to ↑↑↑↑ along the Cotrig-(Co/Mn)oct-Cotrig-(Co/Mn)oct spin chain. For x=0.6-0.3, however, the magnetization curve presents a single metamagnetic transition, which can be understood as a ↑↓↑↑ to ↑↑↑↑ transition. The zero-field ↑↓↑↑ structure is further supported by the results of total energy calculation of x=0.5.