Depression of critical temperature due to residual strain induced by PLD deposition on YBa2Cu3O7-δ thin films

Highlights: • Residual strain on thin films of Y Ba₂Cu₃$O_{7-\delta }$ grown by PLD deposition. • Linear depression on T_c with c-axis elongation. • Possible explanation of T_c drop by a quantum fluctuations model. We present the study of a high $T_c$ superconductor under residual strain. We study the growth of a series of thin films of $YB{a}_{2}C{u}_3{O}_{7-\delta }$ (YBCO) using the Pulsed Laser Deposition (PLD) technique. The samples exhibit a residual in-plane compressive strain, whose degree depends on the growth conditions and the thickness of the film, and which alters the superconducting behavior. A thorough characterization of the system, correlating structural and superconducting properties is presented. Raman spectroscopy is introduced to characterize the samples and rule out oxygen loss effects. A possible explanation for the nearly linear depression of the critical temperature $T_c$ with c-axis expansion was introduced, in terms of the mutual Coulomb screening of charge fluctuations along the c-axis, between consecutive $Cu{O}_2$ planes in the structure.