Nano-crystal LaNiAl film with helium charged

Nano-crystalline LaNiAl film charged with helium atoms is prepared by magnetron co-sputtering. Low energy helium-4 atoms implantation is carried out by magnetron co-sputtering technique with Ar/He mixture gases around during the film growth. During the sputtering process, the ionized He atoms bombarding the cathode target are backscattered and implanted into the growing film. The film is CaCu5-type structure analyzed by XRD. Helium concentration is measured by proton backscattering spectroscopy (PBS), the most atom fraction of helium is 12.2%. Deduced by thermal desorption experiments and TEM, helium exists as He-V cluster in the nano-crystal films. Compared with 3He in a tritide, the implanted He in metal film is still quite different, but it is a good way to study how helium atom exists in La-Ni-Al inter-metallic compound.