GdOGd dimer formation in xGd2O3 · (1 - x)Na2O · 2B2O3 glasses

EPR and magnetic susceptibility studies of B2O3–Bi2O3–Gd2O3 glasses

“…glasses are in agreement with those previously reported for other oxide glasses containing gadolinium ions [5][6][7][8] and support the EPR results presented in this study.…”

“…1. These spectra are due to the presence of Gd 3+ ions in the B 2 O 3 AE Bi 2 O 3 host matrix and are relatively close to those previously reported for other oxide glasses containing gadolinium ions [5][6][7][8][9][10][11][12][13][14]. For low gadolinium concentrations in glass matrix the EPR spectra is characterized by prominent features with effective g eff values of %6, %4.8, %2.87 and %2 and at higher concentration being superimposed on a broad resonance line shape that encompasses the prominent g eff % 2 feature.…”

“…Most of the authors consider the mentioned absorption features (g eff % 6, g eff % 2.87, g eff % 2) to be generated by Gd 3+ ions disposed in cubic, octahedral or tetraehedral sites with moderate distortions. In these sites the gadolinium ions experience a relatively weak crystalline field and they are characterised by a coordination number higher than six [5][6][7][8][9][12][13][14]. The difference between Gd 3+ EPR spectra of xGd 2 O 3 AE (100 À x)[B 2 O 3 AE Bi 2 O 3 ] glasses and the 'U' spectrum is the occurence of an asymmetric absorption line with g eff % 4.8.…”

“…But for x = 10 mol% the narrowing of the EPR signal can be balanced by the broadening effects due the progressive disordering of the vitreous structure. At higher gadolinium contents, isolated Gd 3+ ions can coexist with clusters of Gd 3+ ions linked with each other by exchange interaction through the oxygen bridges [5][6][7][8][9]. Fig.…”

“…In the last decade, oxide glasses such as borate [5,6], bismuthate [7,8], boro-tellurite [9], germanate, phosphate [10], and other oxide glasses [11] doped with gadolinium ions were studied by means of EPR and magnetic susceptibility measurements.…”