Pressure Dependence of Superconductivity in Filled-Skutterudite YOs4P12

We have studied the magnetization on YOs4P12 under pressure up to ∼ 4 GPa. Pure polycrystalline YOs4P12 was prepared by the high-pressure high-temperature method and was evaluated by the X-ray diffraction measurement. YOs4P12 shows superconducting transition at TSC ∼ 3K at ambient pressure. We have investigated the pressure dependence of TSC by means of DC magnetization measurements with incorporating opposed ceramic anvil pressure apparatus into MPMS. TSC of YOs4P12 slightly decreases with pressure at a rate of dTSC/dP = -0.11K/GPa. This is quite contrary to the TSC of related compounds YFe4P12, which rapidly increases with pressure at a rate of 1.0K/GPa. The dTSC/dPs relationship of YFe4P12 and YOs4P12 are similar with that of LaFe4P12 and LaOs4P12. TSC of LaFe4P12 increases rapidly with pressure at a rate of dTSC/dP ∼ 0.72K/GPa below 2GPa and that of LaOs4P12 decreases gradually with pressure at a rate of -0.095K/GPa. Considering these similarity, we can assume that the origin of dTSC/dP of these compounds are the same and are attributed to the density of states at Fermi level and to the Hopfield parameter.Conference : 20th International Conference on Magnetism, ICM 2015Location : Barcelona, SPAINDate : JUL 05-10, 201

Pressure Effect on the Structure and Superconducting Transition Temperature of Filled Skutterudites LaT4P12 (T=Fe, Ru)

We studied the effect of pressure on the superconducting transition temperature TSC of LaT4P12 (T=Fe, Ru) up to 8 GPa through electrical resistivity measurements in a cubic anvil apparatus. The TSC of LaFe4P12 was also determined through magnetization measurements up to 3.4 GPa with an opposed-anvil pressure cell. In LaFe4P12, TSC increases with pressure at a rate of 0.71 K/GPa from 0 GPa reaching its maximum at approximately 7 GPa. In contrast, the TSC of LaRu4P12 monotonically decreases with pressure. The decrease rate gradually increases from −0.07 to −0.29 K/GPa. The distinct pressure dependences of both TSC\u27s cannot be explained solely from a structural point of view. We propose that the difference between the pressure dependence of TSC for LaFe4P12 and that for LaRu4P12 can be attributed to the difference in the electronic density of states at the Fermi energy between these two compounds

Magnetic properties of new filled skutterudite compound BaFe4As12

The magnetic, electrical and thermal properties of a new As-based alkaline-earth-filled skutterudite compound BaFe4As12 prepared under high pressure have been studied at low temperatures. The temperature dependence of the electrical resistivity for BaFe4As12 reveals a metallic behavior. Any anomalies accompanied by phase transition were not observed down to 2K. A broad maximum of magnetic susceptibility around 50 K and a large electronic specific heat coefficient of 62 mJ/molK2 suggest that BaFe4As12 is a nearly ferromagnetic metal with spin fluctuations of Fe 3d electrons