Deconvoluting interrelationships between low-energy vibrational modes and elastic properties in CaO-Al2O3 glasses

By employing a nonconventional melting technique, namely, the aerodynamic levitation combined with CO2 laser melting, we have been able to synthesize a series of glasses in the binary system xCaO - (1 - x)Al2O3, (x = 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, and 0.80). Utilizing Raman spectroscopy, we have systematically followed the compositionally induced spectral changes in the low-frequency regime of the spectra, the so-called Boson Peak (BP) region, and unraveled interesting interrelationships between the low-energy vibrational modes and the elastic properties of calcium aluminate (CA) glasses. It was found that the BP frequency is not only systematically dependent on altering CaO content by exhibiting a minimum close to the eutectic composition. Interestingly, the above-mentioned compositional dependence of the BP, which is exhibited in the shift of the BP frequency versus the altering CaO content, is also strongly correlated with its elastic properties and seems to follow similar patterns for the binary CA glassy system. The above observations point toward the estimation that the eutectic point can serve as a strong indicator for various physicochemical phenomena taking place in the solid-liquid transition and thus provide new insights in an effort to deconvolute the ambiguous interrelationships occurring in the low vibrational frequency regime of these glasses.

Automated summary

By utilizing a nonconventional melting technique, researchers synthesized a series of calcium aluminate glasses and investigated the relationship between the low-frequency spectral changes and elastic properties. The study revealed a systematic dependence of the Boson Peak frequency on the CaO content, which is correlated with the elastic properties.