High temperature EPR study of the M₃Fe₄V₆O₂₄ (M = Cu, Zn, Mg and Mn)

Electron paramagnetic resonance (EPR) spectra of M₃Fe₄V₆O₂₄ (M = Cu, Zn, Mg and Mn) compounds in high temperature range (293 K to 493 K) have been investigated. The role of magnetic (Cu, Mn) and non-magnetic (Zn, Mg) ions in M₃Fe₄V₆O₂₄ structure in formation of magnetic resonance spectra was studied. Temperature dependence of EPR parameters: resonance field, linewidth and integrated intensity were examined. Similarities and differences in temperature behavior of these parameters has been discussed in terms of different relaxation mechanisms and magnetic interactions in the spin systems. An important role of additional magnetic ions (M = Mn or Cu) in the M₃Fe₄V₆O₂₄ structure has been identified and its consequences considered.