Everton striker Vaughan, 21, has joined Derby on loan in an attempt to improve his fitness levels.
Vaughan has made 49 appearances for Toffees and scored on seven occasions since making his debut in April 2005.
Newcastle have signed the Blackburn Rovers defender Zurab Khizanishvili on a three-month loan. The Georgia international, 27, has only featured once for Rovers this season.
"He knows English football very well and will be a valuable addition to the squad over the coming months," the Newcastle manager Chris Hughton told the club's official website.
Khizanishvili has been at Ewood Park since the summer of 2005, having previously played in Scotland for both Dundee and Glasgow Rangers.
Plymouth Argyle have signed the defender Shane Lowry on a three-month loan deal from Aston Villa.
Lowry, 20, has featured twice in the Villa first team as a substitute this season, playing in both legs of the Europa League tie with Rapid Vienna.
And after a day of signings, here is a player not moving: the Nottingham Forest manager Billy Davies has said Robert Earnshaw is not for sale.
The striker, 28, is rumoured to have attracted interest from Middlesbrough and Newcastle United and started just one league game for Forest this season.
"Robert Earnshaw isn't for sale, he isn't going anywhere. He's part of a six-man strikeforce that we've put together for a reason. He's here to fight for his place and to play a part in this squad of players," Davies told the Evening Post.
"There's been speculation linking him with other clubs, but let me make it clear, we don't want to sell him, we won't sell him. He's very much part of this football club and has an important role to play."