Structural and electrical transport properties of FeH_x under high pressures and low temperatures

Abstract

We present the first successful in situ simultaneous measurement of the electrical resistance and X-ray diffraction of FeH _x (x∼ 1) under high-pressure H₂ up to 25.5 GPa and low temperatures down to 9 K. The electrical resistivity ρ showed a sharp increase with the formation of iron-hydride FeH _x (x∼ 1) at 3.5 GPa. The ϵ′-phase of FeH _x was found to be metallic up to 25.5 GPa. The ρ vs. T curves up to 16.5 GPa approximately follow Fermi-liquid law below 25 K. However, T ⁵ was found to be better fitting at 25.5 GPa. This change can be considered to be related to the previously reported ferromagnetism collapse at corresponding pressure.

Keywords:

• iron-hydride
• electrical resistance
• X-ray diffraction
• diamond anvil cell
• magnetism
• structural transition

Acknowledgements

This work is supported by the HYDROSTAR Project provided by the New Energy Development Organization (NEDO).