Certainly not academic articles in peer-reviewed journals. Reason being, the PhD experience should advance you, intellectually, to such a level as to put into the shade any of your previous publications. There may be some doctoral candidates who are exceptions to this rule but not many. For the vast majority of PhD candidates any serious publications can only come after the completion of the doctorate, not before. And be sure, every PhD supervisor knows this. So when they consider your application they are not looking for proof of doctoral ability but evidence of potential along with durability.

Yes, usually you publish papers after you have completed your PhD :)