Abstract
Recent experimental techniques of producing extreme conditions of ultrahigh pressure at very low temperature and also of measuring magnetic and electrical properties of matters are described. The pressure tool shown in this article is limited on diamond anvil cell (DAC), as the DAC is almost unique for assembling on 3He/4He dilution refrigerator and producing the highest pressure exceeding 100GPa at 50mk. Electrical and magnetic measurements for samples confined in DAC is difficult because of the extremely small size (-10-8cc). Recent development of the measuring techniques is also discussed and the electrical resistance measurement of solid oxygen under pressure of 120GPa, in which the superconductivity appears at low temperature of 0.6K, is given as an example.
