Crystal structure and magnetic properties of the solid-solution phase Ca3Co2–vMnvO6

The homogeneity range of the Ca3Co2–vMnvO6 solid-solution phase covers the entire composition interval from v=0 to 1. A systematic powder X-ray and neutron diffraction, magnetic susceptibility, and magnetization study has been carried out to investigate effects of the Mn-for-Co substitution on structural and magnetic properties. The Mn substitution concerns primarily only the octahedral Co1 site of the Ca3Co1Co2O6 crystal structure, whereas the trigonal-prismatic Co2 site structurally is left essentially unaffected. The Ca3Co2–vMnvO6 crystal structure belongs to space group R3¯c with unit-cell dimensions (in hexagonal setting) 9.084⩽a⩽9.134 Å and 10.448⩽c⩽10.583 Å. A cut through the magnetic phase diagram at 10 K shows a ferrimagnetic domain for 0⩽v<∼0.3 and an antiferromagnetic domain for ∼0.50

Diagonal cut through the rhombohedral crystal structure of Ca3Co2–vMnvO6 (crystallographic formula, Ca3Co11–vMnvCo2O6) with emphasis on its characteristic one-dimensional columnar traits.Magnetic moments on the transition metal sites order parallel to [001] below ∼25/18 K. For 0⩽v<∼0.3 the state is referred to as ferrimagnetic although this designation becomes increasingly approximative as v increases. For ∼0.5