Factors influencing the concentration of V (IV) complexes and the parameters of the spin hamiltonian in phosphate-vanadate semiconducting glasses

Abstract

The dependence of the components of the g tensor and the HFS constant of the complex VO040 in phosphate-vanada te sere[conducting glasses of the system mV205 �9 (100-m)P205 (m = 100-2) and the nonsemiconductin g glasses 24CaO.V205. 25P205 and 24BaO.V2Os" 25P205 on the concentration of V(V), P(V), Ca 2+, and Ba 2+, joined to V(IV) through oxygen ligands, has been examined. The parameters of the spin Hamilton[an, the splitting of the 3d level (that is, themagnitude of the energy of the d-d transition) of the V(IV) ion in the field of the yl oxygen and the in-plane oxygen ligands, and the mechanism of electrical conductivity have been determined. The aim of the present work was to study the dependence of the parameters of the spin Hamiltonian (SH), the nature of the chemical bonding, the concentration of unpaired electrons, and the splitting of the energy levels of the 3d V(W) ion in the field of the oxygen ligands on the composition of phosphate-vanada te semiconducting glasses mV205 �9 (100- m) P20. 5 (I) (m = 100- 2) and the nonsemiconductia g phosphate- vanadate glasses 24 CaO" V205 "25P205 (I_D and 24BaO. V205- 25P205 (III) by ESR and electronic absorption methods. The parameters of the SH, gs gll' A-t' and AII were determined more accurately in the present work than in earlier work [1, 2]. The ESR studies were carried out on an Rt~-1301 spectrometer at 77 and 295~ The diffuse reflectance spectrum was recorded using the monochromator of an MOM-201 spectrophotomete r and a PDO-1 diffuse reflectance attachment [3].