Construction of Constant Pressure Generator and AC calorimetric measurements of Ce_2RhIn_8

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It was succeeded in constructing the constant pressure generation system under the pressure up to 4GPa and in the temperature down to 0.75K. The important point to make it possible is using MP30 metal for pressing rod. This is the first system of the world.We have also constructed the ac caloric measurement system for low temperature and high pressure. In order to make it possible to measure ac calorimetric data, we constructed the new spot welding system. It was spot welded 20 μm Au and Au-Fe0.07 thin wire thermocouples on the samples. We have been measured the heat capacity of CePd_2Si_2 and Ce_2RhIn_8 for the test of this measurement system. It is clearly seen that the anti-ferro magnetic ordering temperature T_N decreases increasing pressure and the jump at T_N smears under the high pressure. This result suggests that Kondo temperature increases and magnetic fluctuation is dominated under high pressure in this material.