Investigation of ferromagnetic filled skutterudite compound EuFe4As12

Abstract

A variety of thermodynamic and transport measurements were performed on As- based filled skutterudite compound EuFe4As12 prepared under high pressure. EuFe4As12 was reported to exhibit a ferromagnetic-like phase transition with an unexpectedly high transition temperature of 152 K. In order to investigate the field dependence of the transition in the arsenide, specific heat measurements under magnetic fields up to 8 T have been carried out. The ferromagnetic-like transition is clearly visible as a peak of the specific heat at 0 T. The anomaly for the phase transition was found to become broad and shift to higher temperature with applying magnetic field. This behavior is consistent with a ferromagnetic ordering. Furthermore, the excess magnetic entropy suggests a possibility of the magnetic contribution of the [Fe4As12] polyanions. We will discuss the magnetic ordering state from a viewpoint of the interaction of Eu 4f moments with the ferromagnetic [Fe4As12] host lattice. From the measurements of thermoelectric properties, the dimensionless figure of merit ZT was evaluated as 0.007 at room temperature.