Abstract
We have studied the electrical resistivity of the filled skutterudite compound under high pressure. The antiferroquadrupolar ordering temperature decreases monotonically with increasing pressure up to . Above , we have found that a metal-insulator 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 transition. is an unusual compound in that it shows a pressure-induced transition from a metal to an insulator.
- Received 21 October 2004
DOI:https://doi.org/10.1103/PhysRevB.71.073102
©2005 American Physical Society