J.L. Nowinski

Studies of Li2O–V2O5–P2O5 glasses by DSC, EPR and impedance spectroscopy

Abstract Glasses of the Li 2 O–V 2 O 5 –P 2 O 5 system of different extent of glass-network disruption, characterized by a parameter r =[Li 2 O]/[V 2 O 5 +P 2 O 5 ], were synthesized. They were subsequently characterized by differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR) and impedance spectroscopy. As in the case of glasses of the Ag 2 O–V 2 O 5 –P 2 O 5 system, studied earlier by us, one observes a transition from predominantly electronic to predominantly ionic conduction. EPR spectra of predominantly ionically conducting glasses under study exhibit hyperfine structure (hfs). In the case of electronically conducting glasses, the hyperfine structure of EPR lines is absent.

Compressibility investigations of AgI-Ag2O-P2O5 superionic materials

Abstract The novel method with the use of resistance foil strain gauges is described and employed for the determination of the isothermal volume compressibility coefficient of x AgI–(1− x )(Ag 2 O–P 2 O 5 ) (0.05≤ x ≤0.5) glasses. It has been found that compressibility is dependent on pressure–time–history of the glass. The results are discussed and explained on a model assuming that high pressure causes the network to be more densely packed resulting in lower compressibility. Also, concentration of AgI in the glass affects the compressibility value. The linear dependence of compressibility vs. molar fraction of AgI has been found. The linear model of resultant compressibility of composite materials has been suggested to explain the observations.

Glasses of AgIAg2OP2O5 system containing AgI crystalline precipitates

Abstract Glasses of the composition xAgI·(1−x)AgPO3 (0.4≤x≤0.8) with AgI precipitates have been studied using X-ray diffraction, optical microscopy, DSC and admittance spectroscopy. The results obtained indicate that highly doped samples (x≥0.7) contain a glassy phase with AgI content of ca 55 mole%, and AgI precipitates in the form of dendrites. This two-phase material is thermally stable.

The electrical properties of AgI−Ag2O−P2O5 glasses with high AgI content

Glasses of composition x Agl·(1− x )AgPO 3 , 0.2≤ x ≤0.8 were studied by admittance spectroscopy, DTA, X-ray diffraction, optical and scanning electron microscopy. For the composition with x ≈0.63 the ionic conductivity was maximal while the activation energy E a and the glass transition temperature T g were minimal. In AgI rich samples crystalline γ and β-AgI precipitated in the form of dendrites. Samples with x >0.7 exhibited the same value of E r and T g as the glass with x ≈0.55. We propose that the glassy phase which remains after precipitation of AgI dendrites contains only about 55 mol% AgI.

The electrical properties of 0.45Li2O·0.55B2O3 glasses doped with Al2O3 or LISICON

Abstract The electrical properties of 0.45Li 2 O·0.55B 2 O 3 glasses doped with Al 2 O 3 or LISICON are reported. Al 2 O 3 proved to be partially dissolved in this glass and caused higher activation energy and lower value of electrical conductivity as compared to those of undoped glass. In the case of LISICON dopant the dissolution was complete and changes in electrical properties of LISICON-doped glass were observed.

Applicability of the Meyer-Neldel rule to selected single crystal, ceramic and glassy superionic conductors

Abstract The applicability of the Meyer-Neldel (M-N) rule to several crystalline and amorphous superionic conductors is examined. The interpretation of the constant α in the M-N dependence is proposed.

Some properties of the AgIAg2OP2O5 glasses doped with Al2O3

Abstract The influence of Al 2 O 3 doping on electrical properties, glass transition temperature, density and microhardness of 0.4AgI·0.6AgPO 3 glass is described. It is supposed that the dopant reacts with glass forming precipitates of a new crystalline phase.