Study of the hyperfine structure, thermal stability and electric–dielectric properties of vanadium iron phosphate glasses

Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

“…This is in a good agreement with the recently reported investigation of lithium iron phosphate glasses, 34 where the interface regions between nanocrystallites and amorphous phase rich in Fe 2+ and Fe 3+ pairs were crucial for the increase in conductivity. Similar results were obtained for xCr 2 26,27 It is important to note that the structural changes in this glass system are also reflected in the shape of the impedance response in complex plane, Figure 9. All glassy samples show single semicircle indicating single polaronic conduction mechanism.…”

“…In particular, the addition of V 2 O 5 or AgI to some silicate and phosphate glasses can increase this value even up to 10 −3 (Ω cm) −1 . 2,3 The ability of glass to conduct electricity, therefore, depends strongly on the composition. Naturally, the glass composition determines the type of charge carriers.…”

Effect of heat treatment on the hyperfine structure and the dielectric properties of 40P2O5–40V2O5–20Fe2O3 oxide glass

“…The same conduction mechanism was found also for vanadium phosphate glasses where electron hopping occurs from V 4+ sites to the neighboring V 5+ sites [4,5]. Shapaan et al [6] studied the hyperfine structure, thermal analysis and the electric-dielectric properties of the ternary vanadium iron phosphate glass system (60 À X) P 2 O 5 (20 + X) V 2 O 5 20Fe 2 O 3 (X = 10, 15, 20, 30 and 40 mol%) in more details. It was found that the vanadium ions play the role of glass network modifier (GNM) and the electric conduction in this glass system attributed to small polarons hopping (SPH).…”

Influence of the Structure on Magnetic Properties of Calcium-Phosphate Systems Doped with Iron and Vanadium Ions

“…As a consequence of hopping an unpaired 3d 1 electron from the V 4+ site to the V 5+ site, electrical conduction occurs. The possibility of the vanadium ion to change its oxidation state during the melting and quenching process of glass preparation was reported in the literature [ 23 , 24 , 25 , 26 ]. The data reveal structural changes of the units due to the formation of bonds between non-bridging oxygen and iron atoms in different coordination, while the increase in the content of vanadium ions in the samples leads to the decrease of the activation energy [ 23 , 24 , 25 , 26 ].…”