Pressure-induced metal-insulator transition in the filled skutterudite PrFe4P12 -: art. no. 073102

We have studied the electrical resistivity of the filled skutterudite compound PrFe4P12 under high pressure. The antiferroquadrupolar ordering temperature T-Q decreases monotonically with increasing pressure up to 2.4 GPa. Above 2.4 GPa, we have found that a metal-insulator (M-I) transition appears. The insulating state is easily suppressed by a magnetic field. The observed Kondo effect and a field-induced heavy-fermion state at high pressure suggest that the quadrupolar interactions survive in the insulating region. The quadrupolar interactions might play an essential role in the M-I transition. PrFe4P12 is an unusual compound in that it shows a pressure-induced transition from a metal to an insulator.