Preparations and applications of Highly Concentrated Metal Hydrides

我们已经形成了高度浓缩的金属氢化物形成金属间化合物，以改变其电学和磁学性质如下：可以制备Mg_2NiH_x、FeTiH_x、LaNi_5H_x和LaCo_5h_x薄膜。通过闪蒸在玻璃基板上制成的薄膜在高压下与氢反应。氢化物膜在多次加氢和脱氢反应中都很稳定。Mg_2NiH_x薄膜的吸收光谱显示，吸收边缘位于1.6eV附近。这与结构I （1.36eV）的计算值一致，而与结构II （0.8eV）的计算值不一致。这是对半导电性金属氢化物带隙的首次测量。测定了LaNi_5H_x和LaCo_5H_x薄膜的霍尔系数随氢压力和温度的变化。这些物质表现出反常的霍尔效应。可能是Ni或Co粒子在吸氢过程中发生了偏析。以YCo_3为基料，部分用Ni或Fe取代Co，通过改变Ni或Fe含量来控制吸氢平衡压力。Y(Co/Ni/Fe)_3化合物氢化物的磁性能与氢的组成密切相关。

We have formed highly concentrated metal hydrides form intermetallic compounds to modify their electrical and magnetic properties as follows:1. The films of Mg_2NiH_x, FeTiH_x, LaNi_5H_x and LaCo_5h_x can be prepared. The films which are made on glas substrates by means of flash evaporation are reacted with hydrogen at a high pressure. The hydride films are very stable against several cycles of hydriding and dehydriding reactions.2. The absorption spectrum of the Mg_2NiH_x film shows that the absorption edge is located near 1.6eV. This agrees with the calculated value for Structure I (1.36eV), rather than that for structure II (0.8eV). This measurement is the first finding about the band gap of a semiconductive metal hydride.3. The Hall coefficients of LaNi_5H_x and LaCo_5H_x films have been measured as a function of hydrogen pressure and temperature. These substances show the anomalous Hall effect. It is likely that Ni or Co particles are segragated during hydrogen absorption.4. The hydrogen absorbing alloys have been developed, which are based on YCo_3 and partially substituted substituted with Ni or Fe for Co. We can control the equilibrium hydrogen pressure by variying the Ni or Fe content.5. The magnetic properties of the hydrides of Y(Co/Ni/Fe)_3 compounds depend strongly upon hydrogen composition.