Effect of Zn2+ substitution on magnetic properties of the quasi-one-dimensional spin chain compound Ca3CoMnO6

Abstract

The subtle variation of magnetic structure has large influence on the macroscopic magnetism of Ca3CoMnO6. As the isovalent nonmagnetic ions have no exchange interaction with the adjacent Co2+/Mn4+ and it could keep the valence states and spin states of the Co/Mn ions unchangeably. Introduction of isovalent nonmagnetic ions thus becomes an ideal selection for us to understand the relevant micromechanism. In this paper, a series of Zn2+ substituted Ca3Co1-xZnxMnO6 (0 ≤ x ≤ 0.2) samples were prepared, and the microstructure and magnetic properties were investigated in detail. The XRD results indicate that for low doped samples the larger radius of Zn2+ causes the lattice parameters and volume increase. While for high doped samples the Zn2+ ions enter the octahedral position, resulting in shrinkage of the lattice. The introduction of Zn2+ ions could also influence the magnetic structure of Ca3CoMnO6 effectively. A small amount of nonmagnetic Zn2+ ions well decrease the concentration of the intrinsic defects and help to form more short-range magnetic order. But as the Zn2+ doping concentration increases, the main effect of Zn2+ doping is to release the magnetic frustration of Ca3CoMnO6, and finally a more robust long range antiferromagnetic structure can be established in high doped samples. Simultaneously, the subtle variation of magnetic structure with Zn2+ substitution leads the Ca3Co1-xZnxMnO6 samples present different dynamic behaviors. This interesting finding could serve as a new reference for tuning the magnetic ordering of Ca3CoMnO6 and improving its multiferroic properties.