Transport and Magnetic Properties of Pressure-Induced Insulating Phase in PrFe₄P₁₂

Abstract

We have studied the physical properties of a pressure-induced insulating phase in PrFe₄P₁₂ via Hall effect, ³¹P-NMR and magnetization measurements under quasi-hydrostatic pressure. In the Hall effect measurement, a decrease in the number of hole carriers due to the metal–insulator (M–I) transition is confirmed, indicating a band insulating state. The ³¹P-NMR spectrum exhibits abrupt broadening and the susceptibility is suppressed markedly owing to the M–I transition, suggesting that an antiferromagnetic ordering occurs in the insulating phase and the M–I transition is of first order. Both spectra corresponding to the metallic and insulating phases are observed simultaneously in a wide temperature range near the M–I transition. This fact reflects the sensitivity of the M–I transition to uniaxial stress, which is confirmed in the resistivity measurement under uniaxial stress.