Microstructural features of coevaporated Nb3Ge films

The microstructure of coevaporated Nb3Ge films was studied by means of transmission electron microscopy (TEM). Large area inspection of this material with reproducible high Tcshows two kinds of grains sized about 200 Å and 1000 Å in diameter, respectively, with an overall average size of 600 to 800 Å. Images of various lattice defects could be seen, especially a large amount of low angle boundaries with different types of characteristic moiré patterns. Two states of the Nb5Ge3phase have been revealed by dark field imaging: a lamellar and a granular structure. - Some high resolution structure images of Nb3Ge are shown.