High-pressure synthesis, electrical and magnetic properties of new filled skutterudites LnOs4P12 (Ln = Eu, Gd, Tb, Dy, Ho, Y)

Abstract New filled skutteudites LnOs 4 P 12 (Ln: Eu, Gd, Tb, Dy, Ho and Y) have been prepared at high temperatures and at high pressures. X-ray diffraction of these compounds is studied at room temperature. The relationship between lattice constants and atomic numbers of lanthanide (including Y) is obtained for LnOs 4 P 12 (Ln: lanthanide). Electrical and magnetic properties of the new filled skutterudites with heavier lanthanide have been investigated at low temperatures. EuOs 4 P 12 and GdOs 4 P 12 show ferromagnetic transitions at around 15 and 22 K, respectively. The valence states of both compounds are +2 for the Eu compound and +3 for the Gd compound. DyOs 4 P 12 does not show the magnetic transition down to 2 K. However, a small electrical anomaly is found at around 10 K. YOs 4 P 12 exhibits a superconducting transition at around 3 K. This compound is a new superconductor. Electrical and magnetic anomalies of new filled skutterudites with heavier lanthanide LnOs 4 P 12 (Ln: Eu, Gd, Dy and Y) are discussed. We have also found the electrical anomaly based on the magnetic transition at around 22 K for GdFe 4 P 12 .