In-Situ Temperature Measurement Of Experimental Study In Diamond Anvil Cell

At present, high-temperature and high-pressure experiments should be combined with advanced testing methods (synchrotron radiation, Raman diffraction, X-ray diffraction spectra, Hall testing system, etc.). Diamond anvil cell (DAC) is a commonly used ultrahigh-pressure device, and suitable for in-situ measurement in high temperature and high pressure experiments. With DAC, a variety of material information under high temperature and pressure conditions can be obtained.In-situ temperature measurement under high pressure is very difficult. It depends rigorously on experimental technique, which results in correlative systematic researches are ceased and suspended. Especially in DAC, samples for high-pressure experimental are usually surrounded in a metal gasket; therefore it is hard to arrange the temperature–detecting probe in sample chamber. However, thin-film thermocouple can solve this issue satisfactorily.Although there are a variety of methods that can be utilized in high temperature and high pressure experiments, for certain technical difficulties, laser heating DAC technique (LHDAC) are mainly used.Compared with the LHDAC thin-film thermocouples have many advantages as following: (1) It can be placed with very high accuracy on a given position. (2) Volume changes can be ignored. (3) Its position can be fixed under high pressure. (4) In-situ temperature measurement can be implemented in a very small space. The thermocouples in our experiments are W-Ta thin film thermocouple which is fabricated on DAC by a radio frequency sputtering system.After complete the testing of W-Ta Thin-film thermocouple, we have received the following information: In the pressure of 1.37 GPa, 3.58Pa, 8.64Pa, the thermoelectric potential value steadily increased with the temperature, and showed a good linear relationship. Moreover, the thermoelectric potentials at these pressure points are equal, which indicates that it do not change with the pressure. For W-Ta metal thin film thermocouples that is the further evidence of applicability in-situ temperature measure.