If you use a terracotta pot get a low wide one, perhaps like they use for bonsai, and get some aluminium fly wire big enough so that it can be bend over the sides. First cut a hole in the middle big enough to put the AZ's roots through, fill the pot with the substrate you use and bury in substrate of the tank. The advantage with using a wider pot is that there will be stuff settling and breaking down around the roots so the plant can have some nutrition and remain the pride of your setup.