Positron Annihilation in Ni₃Ga

After confirming by magnetization measurements that a Ni 3 Ga single crystal is purely paramagnetic, the two dimensional electron-positron momentum density is measured and subsequently the LCW folded density is constructed. A comparison of the experimental results with complementary independent particle model calculations by APW method leads to a qualitative discussion of electron-positron many-body correlation effects in this system in which the character and the density of the valence electrons differ significantly for each cell of the constituent elements.