Interplay between structure and magnetism in the spin-chain compound (Cu,Zn)2V2O7 -: art. no. 214410

The structural and magnetic properties of the one-dimensional spin-chain compound Cu2-yZnyV2O7 were investigated by means of x-ray diffraction, static susceptibility, and electron spin resonance. The substitution of nonmagnetic Zn2+ for Cu2+ ions induces a polymorphic transition from the alpha phase, found for y<0.15, to the beta phase, which occurs for ygreater than or equal to0.15. This transition has a pronounced influence on the magnetic properties, which can be understood consistently by assuming that the intrachain Dzyaloshinsky-Moriya interaction is present in the alpha phase, but absent in the beta phase. This interpretation is confirmed by a symmetry analysis of the structural and magnetic properties. Our results indicate that the local coordination geometry of Cu in the two phases is decisive for the magnetic properties.