Thermal transport properties and lattice vibration modes in crystalline and amorphous LaMgAl11O19

Thermal energy transport plays a crucial role in determining the performance of LaMgAl11O19-based ap-plications. Herein, we report the inherent thermal transport in crystalline (c-LMA) and amorphous LMA (a-LMA) using atomistic simulations. It is found that c-LMA have a low K comparable to the classical 7YSZ at 300-1500 K, while the K of a-LMA is 8-68% lower than that of c-LMA. The mode decomposition shows that the phonon modes in c-LMA consist of local, normal and diffuse modes, while those in a-LMA consist of local and diffuse modes. The dual-channel model reveals that the thermal conduction in c-LMA is domi-nated by the normal modes at low temperatures (< 420 K) while by the diffusive modes at high tem-peratures, but that in a-LMA results entirely from diffusive modes. This new insight into the thermal transport properties in c-LMA and a-LMA provides a foundation for designing LH-based thermal manage-ment applications.(c) 2023 Elsevier B.V. All rights reserved.