Physical properties of LaFeO₃ and Pr_2-xCe_xCuO₄ superstructures

Charge transfer in electron-doped Sm₂CuO₄ (SCO) and LaFeO₃ (LFO) superstructures (SS) grown by RF sputtering was predicted based on their band structure. STEM-EELS measurements revealed the presence of extra electrons at the interface between SCO and LFO[1]. However, the growth conditions left open questions regarding the actual doping of the SCO layers. We have grown SS of electron-doped Pr_2-xCe_xCuO₄ (PCCO) and LaFeO₃ by pulsed-laser deposition with various thicknesses and annealing conditions. X-ray diffraction confirms the coherent growth of PCCO/LFO SS. Superconductivity is confirmed for selected samples by magnetic susceptibility and resistivity measurements, while the Hall Effect of low resistivity samples was carried out for all temperatures. A strong dependence of carrier density and the critical temperature as a function of annealing conditions and thickness of the SS subcomponents is observed. Our results indicate that charge transfer might not be the only source of charge carriers in these structures as annealing conditions are playing a central role in our PLD-grown superstructures.
[1] F.Y. Bruno et al. , Adv. Mat. 25, 1468 (2013).