Drastic change in ferromagnetic ground state associated with pressure-induced metal-insulator transition in -US

Tateiwa, Naoyuki   ; Haga, Yoshinori   ; Yamamoto, Etsuji  ; Fisk, Z.

Paramagnetic -US is a semiconductor with the band gap of 90 K. The applying pressure on -US induces a weak ferromagnetic state above 0.5 GPa and the phase is understood as "induced moment ferromagnetism". In this study, we have measured the magnetization in -US across the insulator-metal transition at 5 GPa with a ceramic anvil high pressure cell. The spontaneous magnetic moment is strongly enhanced at the transition pressure from 0.04 to 0.4 /U. The ferromagnetic state may be stabilized by the larger carrier concentration.