Thermal characterization of ZnBeMnSe mixed compounds by means of photopyroelectric and lock-in thermography methods

Abstract

In this work, a thermal characterization (measurement of dynamic thermal parameters) of quaternary Zn 1-x-y Be x Mn y Se mixed crystals was carried out. The crystals under investigation were grown from the melt by the modified high-pressure Bridgman method with different Be and Mn contents. The effect of Be and Mn contents on thermal properties of Zn 1-x-y Be x Mn y Se compounds was analyzed, by using the photopyroelectric (PPE) method in the back configuration (BPPE) for thermal diffusivity measurements and the PPE technique in the front configuration for thermal effusivity investigations. Infrared lock-in thermography was used in order to validate the BPPE results. The measured thermal effusivity and diffusivity allowed the calculation of thermal conductivity of the investigated materials.

Effect of the surface roughness on the measured thermal diffusivity of the ZnBeMnSe single-crystalline solids

“…The BPPE is a contact method, in which a good thermal contact between the sample and the sensor is required. Therefore, the obtained value of the thermal diffusivity for the polished sample was also validated using non-contact infrared lock-in thermography (IRT) and it was taken from the already published work [29]. The values obtained for the thermal diffusivity of Zn 0.9 Be 0.05 Mn 0.05 Se crystal, by PPE and IRT were (2.831 ± 0.015) × 10 −6 m 2 s −1 and (2.884 ± 0.062) × 10 −6 m 2 s −1 , respectively.…”

“…On the other hand in the case of the bulk material we have taken the value obtained for polished sample (2.831 ± 0.015) × 10 −6 m 2 s −1 ). The real thermal conductivity of the polished sample was taken from [29] as 5.612 ± 0.068 W m −1 K −1 . Knowing the thicknesses of the layers only thermal conductivity and diffusivity of the damaged layer were to found.…”

Improvements of measurement method for thermal diffusivity from infrared thermal movie

“…Other papers have used only the temperature spatial distribution information. [32][33][34][35][36][37] 2. Experiments…”

Proposal of novel measurement method for thermal diffusivity from infrared thermal movie

“…Moreover, some papers reported the measurement with an infrared still camera instead of an infrared thermometer. 29,[33][34][35] In other words, only either information on the time dependence of the temperature or information on the spatial distribution of the temperature is obtained by an infrared camera. Around 2000, one of the authors had the idea that thermal diffusivity could be calculated from information on both the time dependence and spatial distribution of temperature obtained by an infrared movie camera.…”