ランタン膜の水素化・脱水素化に伴う構造変化 The Structural Change of Lanthanum Thin Films by Hydrogenation and Dehydrogenation
Structural change in hydrogenation and dehydrogenation processes of La films was investigated. La/Pd films were produced at substrate temperatures of 300 K-573 K on a SiO<SUB>2</SUB> substrate using magnetron-sputtering equipment. La/Pd films were hydrogenated under a pressure of 1.0×10<SUP>5</SUP> Pa in a vacuum chamber. Phase transition from La to LaH<SUB><i>x</i></SUB> (2<<i>x</i><3) by hydrogenation resulted in a 6- to 10-fold increase of resistivity. Hydrogenation and dehydrogenation readily occurred near room temperature for La/Pd films. The ratio of the growth direction of  to  changed with substrate temperature in the as sputtered La films. When the growth direction of La film was , the rate of hydrogenation became slow in comparison with that of . The direction of the La films changed to the  direction of LaH<SUB><i>x</i></SUB> after hydrogenation, though the initial directions of La films were  and . The processes of hydrogenation and dehydrogenation may affect oxygen which remains inside the La films. In dehydrogenation at room temperature, LaH<SUB><i>x</i></SUB> (2<<i>x</i><3) was transformed to LaH<SUB>2</SUB>, but not to La.
- 日本金屬學會誌 = Journal of the Japan Institute of Metals
日本金屬學會誌 = Journal of the Japan Institute of Metals 68(9), 776-780, 2004-09-20