The three players will remain at the club until January.
"They are young, but Charlton Under-21s won the treble last year, so they are players ready for senior football," Abbott told BBC Radio Nottingham.
"Where we are in terms of availability and finance, they tick a few of the boxes. Ideally we'd like tried and tested, experienced players, but at this time of year it's not easy to get that sort.
"We we're looking at ones who come highly recommended and can do a nice job and give us a bit of balance and depth."
Notts host Brentford on Saturday.