Electron paramagnetic resonance study of Mn²⁺ and Cu²⁺ spin probes in (Ag₂S) _x(GeS₂)_1-x glasses

Mn2+ and Cu2+ spin probes have been introduced in glassy (Ag2S)x(GeS2)1-x (0 ≤ x ≤ 0.8). The electron paramagnetic resonance spectra related to Mn2+ show a poorly resolved hyperfine structure at g = 2 and a characteristic line at g = 4.3 ascribed to the presence of Mn2+ in the center of GeS4 tetrahedra. For small contents of Mn2+, hyperfine structure is resolved as x increases to the limit x = 0.55 and not resolved when x ≥ 0.6. The Cu2+ probe leads to a well resolved signal when x = 0.4. No signal is observed for x &lt; 0.3. These results seem to confirm the presence of a phase separation domain for x &lt; 0.3 and the changes of the local structure of the probes with the appearance of micro-crystallinity due to the Ag8GeS6 phase when x ≥ 0.55.</p

Electron paramagnetic resonance study of Mn²⁺ and Cu²⁺ spin probes in (Ag₂S) _x(GeS₂)_1-x glasses

Mn2+ and Cu2+ spin probes have been introduced in glassy (Ag2S)x(GeS2)1-x (0 ≤ x ≤ 0.8). The electron paramagnetic resonance spectra related to Mn2+ show a poorly resolved hyperfine structure at g = 2 and a characteristic line at g = 4.3 ascribed to the presence of Mn2+ in the center of GeS4 tetrahedra. For small contents of Mn2+, hyperfine structure is resolved as x increases to the limit x = 0.55 and not resolved when x ≥ 0.6. The Cu2+ probe leads to a well resolved signal when x = 0.4. No signal is observed for x &lt; 0.3. These results seem to confirm the presence of a phase separation domain for x &lt; 0.3 and the changes of the local structure of the probes with the appearance of micro-crystallinity due to the Ag8GeS6 phase when x ≥ 0.55.</p

Mn²⁺ electron paramagnetic resonance study of a sodium borosilicate glass prepared by the sol-gel method

Sodium borosilicate glasses were prepared by the sol-gel method and doped with a paramagnetic manganese probe. X-band electron paramagnetic resonance (EPR) experiments, carried out on powdered samples, showed that even for molar ratios higher than 10%, manganese can be inserted in the glass. EPR results obtained on different doped silica glasses showed that the ability of Mn2+ to be inserted in the glassy network is connected with the presence of alkali species. The bulk location of the probe was confirmed by 29Si nuclear magnetic resonance investigations. EPR results indicated that manganese is located in distorted sites in an octahedral silica environment.</p

Mn²⁺ electron paramagnetic resonance study of a sodium borosilicate glass prepared by the sol-gel method

Sodium borosilicate glasses were prepared by the sol-gel method and doped with a paramagnetic manganese probe. X-band electron paramagnetic resonance (EPR) experiments, carried out on powdered samples, showed that even for molar ratios higher than 10%, manganese can be inserted in the glass. EPR results obtained on different doped silica glasses showed that the ability of Mn2+ to be inserted in the glassy network is connected with the presence of alkali species. The bulk location of the probe was confirmed by 29Si nuclear magnetic resonance investigations. EPR results indicated that manganese is located in distorted sites in an octahedral silica environment.</p

ESR study and dc conductivity of binary glasses of the system (V₂O₅)_x(B₂O₃) _1-x

Glasses of the system (V2O5)x(B2O3) 1-x were prepared by melting and quenching in the domain 0&lt;x&lt;1. Electron spin resonance of V4+ species was investigated at room temperature. Two different VO2+ sites were identified and spin Hamiltonian parameters have been determined for these two sites. Variations of these parameters with composition were studied and dc conductivity measurements were performed on the same samples. DC transport properties were ascribed to thermally activated hopping between localised sites.</p

ESR study and dc conductivity of binary glasses of the system (V₂O₅)_x(B₂O₃) _1-x

Glasses of the system (V2O5)x(B2O3) 1-x were prepared by melting and quenching in the domain 0&lt;x&lt;1. Electron spin resonance of V4+ species was investigated at room temperature. Two different VO2+ sites were identified and spin Hamiltonian parameters have been determined for these two sites. Variations of these parameters with composition were studied and dc conductivity measurements were performed on the same samples. DC transport properties were ascribed to thermally activated hopping between localised sites.</p