Strike little devil in germanium (7)
I believe the answer is:
impinge
'strike' is the definition.
(I've seen this before)
'little devil in germanium' is the wordplay.
'little devil' becomes 'imp' (an imp is a little demon).
'germanium' becomes 'Ge' (Ge is the chemical symbol for germanium).
'imp'+'in'+'ge'='IMPINGE'
(Other definitions for impinge that I've seen before include "Make an impact, or have bearing on" , "Encroach on the pig in me" , "Encroach (upon)" , "Have an effect (upon)" , "Make an impact, encroach" .)