The thing from Another World? (1951)
Scientists and American Air Force officials fend off a bloodthirsty alien organism while at a remote arctic outpost.
Wikipedia has the ending being:
The team retreat to the station's generator room to keep warm, and an electrical "fly trap" is rigged. The alien attacks again, but at the last moment, Carrington emerges and pleads desperately with it, attempting communication. It knocks him aside, walks into the trap, and is electrocuted until it is reduced to ashes.
Never seen it, but I knew there was a 50s movie (and earlier book) on which Carpenter's The Thing (1982) was based. And since this movie is the (or at least my) reference on "Alien in Antarctica movie", I figured it could be this...