Ordering of dopants and potential increase in Tc to near room   temperature
  This paper describes a novel method to increase the resistive Tc of cuprate superconductors to values that might approach room temperature if the method is applied to the so-called underdoped regime. This involves ordering the dopants that provide the holes as well as provide pair breaking. The strategy is to separate the doped regions with lower Tc from metallic but undoped regions with the higher Tc. 
Stuart A. Wolf and Vladimir Z. Kresin
cond-mat.supr-con