Positron annihilation studies in CeNiInH1.60

Doppler broadened positron annihilation spectral lineshape measurements in the temperature range 10 - 260 K have been performed in CeNiInH1.60. The results are compared with that of CeNiIn - the valence fluctuating system, and its isostructural system LaNiIn which has no f electron. The results reveal that the nature of the S vs T curve in the temperature range 10 - 100 K of the hydrogenated system is different from that of the parent system. A comparison of the absolute magnitude of the S parameter of the hydrogenated system with that of the non-hydrogenated one further supports the concept of localization of the 4f electron due to hydrogenation, as predicted earlier from the magnetization measurements. (orig.)