Near constant loss in glassy and crystalline LiAlSi2O6 from conductivity relaxation measurements

Abstract

Articles you may be interested inEffect of pressure on decoupling of ionic conductivity from structural relaxation in hydrated protic ionic liquid, lidocaine HClEffects of ions on the dielectric permittivity and relaxation rate and the decoupling of ionic diffusion from dielectric relaxation in supercooled liquid and glassy 1-propanol Polycrystalline and glassy LiAlSi 2 O 6 are studied by dielectric relaxation measurements for the purpose of characterizing the nearly frequency independent contribution to the dielectric loss ͑near constant loss͒, which is commonly found in glassy ionic conductors independent of the chemical and physical structures. The data show the near constant loss is present in both the polycrystalline and glassy states of LiAlSi 2 O 6 . Further, its magnitude and temperature dependence is comparable in both forms of the same substance. The implications of these findings on the mechanism that gives rise to the near constant loss are discussed.

Atomic-scale measurement of ultraslow Li motions in glassyLiAlSi2O6by two-timeL6Wilkening1, Kuhn2, Heitjans3 2008Phys. Rev. B594500View full textAdd to dashboardCite

“…31. Thus, a nearly constant loss ͑NCL͒ phenomenon observed for glassy and crystalline spodumene via ac conductivity measurements 71 performed at temperatures below 273 K seems to be not reflected in the S 2 -decay curves. Roughly speaking, Li SAE NMR is a method which is primarily sensitive to successful displacements of the charge carriers rather than to strongly localized ͑caged͒ motions ͑see above͒.…”

Molecular dynamics simulations of the dynamics of ions in single and mixed alkali glasses

“…The existence of the NCL was suggested repeatedly over the span of several decades [8][9][10][11][12][13][14][15][16][17][18][19][20], and it is now accepted to be a universal characteristic of ionic conductors although its origin is still not totally clear. From analyses of experimental [20] and molecular dynamics simulation data [33], the NCL occurs in the short time regime when the ions are still caged and before they can diffuse to neighboring sites, indicating that NCL is a determining factor in ion diffusion.…”

“…At sufficiently high frequency or low temperature, the dynamic response of glassy, crystalline and molten ionic conductors changes to e 00 (x) = (A/e 0 )x Àa or r 0 (x) = Ax 1 À a , where e 00 (=r 0 /xe 0 ) is the imaginary part of the complex permittivity, e 0 is the permittivity of vacuum, a is a small positive number, and A is a constant with a weak temperature dependence [8][9][10][11][12][13][14][15][16][17][18][19][20]. Since e 00 (x) varies very slowly with frequency, it is called the nearly constant loss (NCL).…”

Molecular dynamics simulation of ion dynamics in glassy ionic conductors: Evidence of the primitive ion hopping process

“…In addition, there is disorder, which further complicates the problem. However, structural disorder such as present in glassy ionic conductors by itself is not sufficient for solving the problem because qualitatively the same dynamics of ions are found in crystalline ionic conductors [18][19][20][21][22], although disorder usually fosters correlations between the ions. Most workers do realize that the many-body relaxation caused by intermolecular interaction is important in considering structural relaxation and glass transition.…”