Chemical pressure effects on the optimization of T C in T′ electron doped superconducting cuprates

Abstract

We report a systematic variation of the superconducting properties with the Ln 3+ size and x in (Ln) 2−xCe xCuO 4−δT′ compounds. Progressive higher T C's with increasing interatomic Cu-O distances are found at the rate dT C0/d(d Cu−O)∼;240 KÅ −1 in x-optimized samples, having the same density of carriers in CuO 2 layers. Charge transfer mechanisms have been isolated from all the rest modifying T C under pressure. The first can positively contribute to T C in overdoped samples, while the second are estimated to yield dT C0/dP∼;-0.11 K/Kbar.