Is the phrase "You are no longer my wife" considered a divorce?

This phrase is a euphemism that could imply divorce or something else. If you intended divorce by it, then it has occurred, and you may take back your wife before the 'iddah expires, provided it was less than three divorces. However, if you did not intend divorce by it, but rather something else, then no divorce has occurred, and nothing is binding upon you regarding it between you and Allah, because a euphemism does not effect divorce unless accompanied by an intention at the time of utterance.