Non-electronic properties of semiconductors (atomic structure, diffusion)

Kinetics of IV $\to$ III polymorphic transformation in Rb$_{1-x}$Cs$_x$NO$_3$ ($x$ = 0.025, 0.05, 0.1) single crystals

A. F. Khazieva^a, V. I. Nasirov^ab, Yu. I. Aliyev^b, A. G. Dzhabarov<sup>bc

a</sup> Institute of Physics Azerbaijan Academy of Sciences, AZ1143 Baku, Azerbaijan
^b N. Tusi Azerbaijan State Pedagogical University, AZ1000 Baku, Azerbaijan
^c Azerbaijan State Economic University, AZ1001 Baku, Azerbaijan

Abstract: Optical microscopy was used to measure the growth rate of III-modification crystals as a function of temperature during the IV $\to$ III transformation in Rb$_{1-x}$Cs$_x$NO$_3$ ($x$ = 0.025, 0.05, 0.1) single crystals. It is shown that the growth rate of III-modification crystals depending on temperature during the IV $\to$ III transformation is described by the empirical formula: $v_{\mathrm{IV}\to\mathrm{III}}$ = (-0.486 $\Delta T$+0.592$\Delta T^2$-0.0015$\Delta T^3$)$\cdot$10$^{-2}$ cm/s, $v_{\mathrm{IV}\to\mathrm{III}}$ = (-0.49$\Delta T$+0.563$\Delta T^2$-0.0018$\Delta T^3$)$\cdot$10$^{-2}$ cm/s, $v_{\mathrm{IV}\to\mathrm{III}}$ = (-0.437$\Delta T$+0.484$\Delta T^2$-0.0014$\Delta T^3$)$\cdot$10$^{-2}$ cm/s, where $\Delta T=T_{\mathrm{tr}}+T_0$. The activation energy of the process IV $\to$ III transformation was calculated, which is equal to $E$ = 85.5 kJ/mol, $E$ = 82.8 kJ/mol, $E$ = 84.8 kJ/mol.

Keywords: crystals, polymorphic transformations, activation energy.

Received: 29.12.2021
Revised: 10.01.2022
Accepted: 10.01.2022

DOI: 10.21883/FTP.2022.05.52345.9796

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