Crystallochemical and magnetic studies of the mixed pyrovanadates ZnxM2-xV2O7  ( 0 £  x  £ 2) ( M = Ni, Cu)

 

M. Bettach*, M. Zahir

LPCM, UCD, Faculté des  Sciences, Département de Chimie, BP 20, El Jadida 24000  Maroc.

* Corresponding author. E-mail: bettachmohammed@yahoo.fr

Received: 03 December 2008; revised version accepted: 27 March 2009

 

Abstract

     The mixed pyrovanadates ZnxM2-xV2O7 ( 0 £ x £ 2) ( M = Ni, Cu), were prepared by  solid way starting from the reagents ZnO, NiO or CuO and (NH4)VO3. The IR spectroscopy enables us to identify   the V2O74- groups as well as the nature of their conformation. The stability ranges of different phases are delimited by XRD. A continuous solid solution b-(Zn,Cu)2V2O7 is observed in a wide range ( 0.2 £ x £ 2). The phase b-Cu2V2O7 is stabilised at ambient temperature by substitution of 10% of Cu2+ ions by the Zn2+ ions. The pyrovanadates ZnNiV2O7 and ZnCuV2O7 exhibit a ferrimagnetic behaviour explained by the existence of not compensated magnetic sublattices.

 

Keywords : pyrovanadates; zinc; 3d transition elements; ceramic synthesis; X-ray diffraction; solid solution; magnetism.

 


 

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