Topic: Chalcogenide, oxide, hydride materials

  • Prof. Masaru ANIYA

  • Kumamoto University, Japan

  • Department of Physics

P-07_M. Aniya_SSC2021_Model Description of the Viscosity of Glass-Forming Chalcogenides

M. Aniya1*, M. Ikeda2

1 Department of Physics, Faculty of Advanced Science and Technology, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan;

2 Department of General Education, National Institute of Technology, Oita College, 1666 Maki, Oaza, Oita 870-0152, Japan

* E-mail: aniya@gpo.kumamoto-u.ac.jp

Keywords: viscosity, chalcogenide, glass, fragility, fragile-to-strong transition, BSCNF model

Abstract: Understand the viscosity behaviour is of primordial importance in the processing of glass-forming materials. Concerning the temperature dependence of the viscosity, many theories and models have been proposed till now [1]. Some years ago, we proposed the Bond Strength-Coordination Number Fluctuation (BSCNF) model [2]. This model describes the temperature dependence of the viscosity or relaxation time in terms of the mean bond strength, mean coordination number and their fluctuations of the structural units that form the melt.

Recently, the model was applied to describe the unusual temperature dependence of the viscosity of metallic glass-forming liquids [3]. These systems have the propensity that at high temperature the viscosity exhibits a very low activation energy, while at low temperature it exhibits an Arrhenius type behaviour. Interestingly, such kind of behaviour has been also observed in some type of chalcogenide systems [4]. Some authors discuss the unusual behaviour in connection with phase change materials and fragile-to-strong transition [4]. In order to understand better the nature of such behaviour, we analysed the temperature dependence of the viscosity of chalcogenide systems based on our BSCNF model. A part of the result is shown in the Figure. Here, the full lines denote the description based on the BSCNF model [3]. By comparing the result obtained in other systems enable us to discuss what could be the origin of the peculiar viscosity behaviour reported in some glass-forming systems.

References

[1] Koštál, P., Shánělová, J. & Málek, J. (2020). Intern. Mater. Rev. 65(2), 63-101.

[2] Aniya, M. (2002). J. Therm. Anal. Cal. 69(3), 971-978.

[3] Ikeda, M. & Aniya, M. (2019). J. Alloys Comp. 805, 904-908.

[4] Orava, J., Hewak, D. W., & Greer, A. L. (2015). Adv. Funct. Mater. 25(30), 4851-4858.

Acknowledgments

This work was supported in part by JST CREST, Japan, JPMJCR1861 and JPMJCR18I2, and by JSPS KAKENHI No. 20K05080 and 20H02430.