Aw, I just groomed a Yorkie named Missy like this yesterday! My trainer calls it a Daisy cut. It looks really cute. But Brooklyn's right, it's pretty much a modified Schnauzer or Cocker cut.
Edit: I would ask your groomer to do a #7F on the back. I find that length won't leave the hair on the back choppy especially if your baby has very silky true to the breed hair.