Elastic Behaviour of Terbium Metaphosphate Glasses Under High Pressures

Abstract

The elastic and nonlinear acoustic vibrational properties of terbium metaphosphate glasses (Tb203)x(P205)1-x with x = 0·226, 0·247, 0·263 and 0·271 (x is the mole fraction) have been determined from measurements of the effects of temperature, hydrostatic pressure, and uniaxial stress on' ultrasonic wave velocity. At temperatures below about 140 K, the elastic stiffness C1J of' (Tb203)x(P205)1-x glasses becomes anomalously dependent upon temperature, a behaviour usually associated with interactions between acoustic phonons and two-level systems. Except for the (Tb203)O·271(P20S)O·729 glass, the hydrostatic pressure derivatives (8C1J/8P)T,P=O of the elastic stiffness C1J and also (8B s /8P)T,P=O of the bulk modulus B S of terbium metaphosphate glasses are small and negative. The third-order elastic stiffness tensor components CIJK of the (Tb203)o·247(P20s)o·7s3 glass between 77 K and 400 K have also been determined. At room temperature, Cl12, C123 and C144 are positive while C111, C155 and C456 are negative. Both longitudinal and shear acoustic mode Griineisen parameters are small and negative: the application of pressure softens the long-wavelength acoustic phonon mode frequencies. The mode softening is enhanced as the temperature is reduced.

Acoustic Vibrational Properties and Fractal Bond Connectivity of Praseodymium Doped Glasses

“…By doing so, it will help to get a better understanding on the dissimilarity of the elastic behaviour under temperature and pressure of these glasses. It is also to see whether the temperature and pressure dependencies of the ultrasonic wave velocities propagated in (Pr 2 O 3 ) x (P 2 O 5 ) 1−x glasses are consistent with those shown by other binary metaphosphate glass system previously studied (Mierzejewski et al 1988;Wang et al 1990;Senin et al 1993Senin et al , 1995Senin et al , 1996Sidek et al , 1993Sidek et al , 1998Senin and Saunders 1999). To achieve the above objectives, the ultrasonic wave velocities and attenuation have been measured at room temperature and as a function of temperature from 10 to 300 K.…”

“…Previous experimental studies using ultrasonic techniques have established that temperature dependencies on the ultrasonic wave velocities propagated in phosphate glasses containing La 3+ (Mierzejewski et al 1988;, Sm 3+ (Mierzejewski et al 1988;Wang et al 1990;Senin et al 1993), Nd 3+ (Sidek et al 1993), Eu 3+ (Farok et al 1994), Ho 3+ (Senin et al 1996), Tb 3+ (Senin et al 1994) and Y 3+ (Senin and Saunders 1999) exhibit a slight difference in this particular property found amongst these glasses. The longitudinal ultrasonic wave velocity of Eu 3+ , Ho 3+ , Sm 3+ and Tb 3+ metaphosphate glasses displays a slight anomalous decrease in the long-wavelength acoustic phonon mode from 300 K down to about 170 K, a behaviour which is associated with the thermally activated structural relaxation of the two-level systems.…”

“…The mixture was then taken out and placed, without cooling, into a second furnace at a temperature of 1000 • C and held for another hour during which the temperature was progressively raised to 1400 • C. Usually the molten glass contains numerous gas bubbles, trapped in the high viscosity mixture. To remove these inclusions, a process of refining was carried out (Senin et al 1996). This procedure was adopted so as to ensure thorough melting, mixing and homogeneity of the glass.…”

Elastic Behavior of Borate Glasses Containing Lead and Bismuth Oxides

“…Modulus of elasticity can be a characteristic of glass since glass is also considered as an elastic substance [24,25]. This modulus increases as the expansion at a certain applied stress reduces.…”

Structural Elucidation of Some Borate Glass Specimen by Employing Ultrasonic and Spectroscopic Studies

“…Glass is considered as an elastic substance and it can be characterized through a modulus of elasticity [19,20]. This modulus increases as the lengthening of certain applied stress diminishes.…”