Measurement of ! H Knight Shift and Magnetic Susceptibility in Compressed Powder Samples of TaH

A valuable experimental method in studying the band structure of metals and alloys is the measurement of the NMR shift of suitable nuclei with respect to a reference signal, the Knight shift (K), see e.g. [1]. Metal-hydrogen systems are an interesting group of metallic solids. The measurement of the proton Knight shift (AH) in metals, however, is somewhat difficult because of its small magnitude, which is in the order of a few ppm. Kazama and Fukai [2] were successful in studying KH on thin metal foils MHV by use of a continuous wave method (CW). Further improvement of the foil method was possible through application of pulsed N M R to systems MH v [3, 4], For many systems MHV the difficulty of manufacturing thin foils arises because of the brittleness of the metal (alloy) of interest. Then the use of fine powder samples of MHV is the only way for determining KH. Within such samples large 'H N M R line widths are observed, mainly due to the inhomogeneities of the magnetic induction at the sites of the nuclei considered. The origin of these inhomogeneities are the demagnetisation fields within the powder sample [5], created by the statistical distribution of the individual grains with respect to their shapes and orientations in reference to the applied induction B0. The contribution to the line width arising thereby is proportional to the volume susceptibility (/v) of the material MHV studied, and