Competing Magnetic Interactions in Zn$\text{}_{3}$Fe$\text{}_{4}$V$\text{}_{6}$O$\text{}_{24}$ Studied by Electron Paramagnetic Resonance

A multicomponent vanadate M$\text{}_{3}$Fe$\text{}_{4}$V$\text{}_{6}$O$\text{}_{24}$ sample with non-magnetic M = Zn(II) ions was synthesized by the solid state reaction method using stoichiometric mixtures of the 80mol% FeVO$\text{}_{4}$ and 20mol% Zn$\text{}_{3}$(VO$\text{}_{4}$)$\text{}_{2}$. The temperature dependence of the EPR spectra was performed in the 90-280 K temperature range. The resonance field and the integrated intensity of the EPR line showed minimum value of both parameters at≈200 K. It is suggested that a part of the sample is displaying tendency to form an antiferromagnetic ordered state (or the magnetic clusters) above this temperature while below the ferromagnetic interaction of the main part of material is dominating. This behaviour is attributed to the inherent magnetic inhomogeneity of the system due to the presence of the ferromagnetic or antiferromagnetic spin clusters.