Non-magnetic to Magnetic Transition under High Pressure in Narrow-Gap Semiconductor [Beta]-US^sub 2

We have measured the magnetization of an uranium chalcogenide compound β-US ... under high pressure by piston cylinder and indenter type cells up to 2.42 GPa in a commercial SQUID magnetometer. The compound is a narrow-gap semiconductor that does not order magnetically down to 0.3 K at 1 bar. The appearance of a pressure-induced phase above 2 GPa was suggested by a previous study with the electrical resistivity measurement under high pressure. In this study, it was found that a ferromagnetic state is induced above 1 GPa. The pressure phase diagram were obtained. The values of the spontaneous magnetic moment at 0 K are less than 0.1 μ ... /U, suggesting that the pressure-induced phase is a very weak ferromagnetic state. Considering the CEF singlet ground state in β-US ... , it is suggest that the ferromagnetic state is an "induced-magnetic phase" often observed in some praseodymium compounds such as Pr ... Tl. The experimental results are discussed in terms of the mean field theory. (ProQuest: ... denotes formulae/symbols omitted.)