Neutron diffraction study of Zn3Fe4V6O24

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

“…Furthermore, detailed structural studies have been presented in earlier papers [3,5,7,13]. EPR measurement in the range of 293 K to 493 K were carried out on Radiopan SE/X 2544-M spectrometer equipped with a homemade high-temperature unit.…”

“…2). The following values of δB r /∆T temperature gradients of that resonance field shift were calculated: δB r /∆T = 7 × 10 −3 mT/K for Cu 3 Fig. 3 shows that three questions should be answered consistently: (a) why the linewidth decreases with temperature increase for all investigated samples below 400 K, (b) why the linewidth is smaller for the compounds with additional magnetic ions (M = Cu and Mn); (c) why the increase of the linewidth above 400 K is observed only for M = Zn and Mg compounds?…”

“…The M 3 Fe 4 V 6 O 24 (M = Cu, Zn, Mg, Mn and Co) compounds have been investigated for some time due to their interesting physical properties and ability to be used in different applications [1][2][3][4][5][6][7][8]. Some of them belong to the howardevansitegroup of minerals and recently two new minerals of this type were discovered in volcanic exhalations from the last eruptions of volcanoes in Kamchatka [9].…”

“…Some of them belong to the howardevansitegroup of minerals and recently two new minerals of this type were discovered in volcanic exhalations from the last eruptions of volcanoes in Kamchatka [9]. The crystal structures of M 3 Fe 4 V 6 O 24 (M = Cu, Zn, Mg and Mn) powders were determined by application of XRD and neutron diffraction methods [1,3,10,11]. The structure contains three sublattices associated with metal ions including two sublattices with iron ions.…”

“…Thus it is evident that the relaxation processes significantly depend on the presence of magnetic ions (M = Cu and Mn) and it is seen that the higher the magnetic moment the more intense change of the EPR parameters of that compound. Despite the fact that their crystallographic structures are well known, one of the main problems lies in determination of the magnetic centres that are responsible for the formation of the observed EPR spectra [3,5,7,8,13]. In [16] it was suggested that there is a strong possibility of the occurrence of magnetic clusters in these compounds.…”