Behavior of Hydrogen in Ta–H System

Abstract

Electrical resistivity, the Hall and thermoelectric effects and proton nuclear magnetic resonance in the Ta–H system prepared electrolytically were measured in the temperature range between 77 and 300 K. X-ray diffraction analysis showed that these samples have the pseudo tetragonal structure which is slightly distorted to the monoclinic, γ=90° 28′ and γ=90° 40′ at 300 and 77 K. In the low temperature phase, the proton resonance line widths are about 11 Oe, and the diamagnetic shift of the resonance field suggests that hydrogen atoms make the partial covalent bond with surrounding atoms. Above 150 K the motional narrowing in the line width occurs and this result shows the rapid motion of hydrogen atoms and its activation energy E_a is obtained to be 0.144 eV.