Epitaxial stabilization of (110)-layered perovskites of the RE2Ti2O7 (RE=La, Nd, Sm, Gd) family

Microstructure and local electrical behavior in [(Nd2Ti2O7)4/(SrTiO3)n]10 (n = 4–8) superlattices

“…Through calculations accounting for the angular position of the satellite peaks, we conrmed the 4 Â 4 periodicity of the synthesized (NTO 4 /STO 4 ) 10 superlattice. Similar results were obtained for the (NTO 4 /STO 8 ) 10 superlattice. Furthermore, the high quality of the diffraction peaks of these superlattices supported the epitaxial growth of these heterostructures.…”

“…1e. Accounting for the deposition rate of NTO, various (NTO 4 / STO n ) 10 superlattices with different n values were deposited on similar substrates with different STO layer thicknesses. Khestanova et al recently reported the fundamental role of the period in such complex articial ferroelectric superlattices.…”

“…Conductivity variations were locally measured for the superlattices using conductive atomic force microscopy (c-AFM), with a higher leakage current obtained for the (NTO 4 /STO 4 ) 10 heterostructure. For this (NTO 4 /STO 4 ) 10 sample, no piezo-signal was obtained by piezoresponse force microscopy (PFM), while apparent piezoactivity was detected on the (NTO 4 /STO 8 ) 10 superlattice that was not primarily due to a pure ferroelectric phenomenon. Such electrical behaviors were principally attributed to point defects in the atomic structure from the substitution of Sr 2+ For the NTO target, a highly dense ceramic, 2.54 cm in diameter and 5 mm thick, was prepared using a classical solidstate reaction pathway.…”

“…Herein, we report the growth of (NTO 4 /STO n ) 10 (n ¼ 4 and 8) superlattices on STO substrates using PLD combined with conventional reection high energy electron diffraction (RHEED) system. In particular, the nanoscale electrical behavior and atomic arrangement were investigated to obtain a better understanding of the physical phenomena of these articial structures.…”

“…From these results, our strategy was to fabricate superlattices with small n values, namely (NTO 4 /STO 4 ) 10 and (NTO 4 /STO 8 ) 10 (74 and 96 nm-thick, respectively). The XRD pattern obtained for the (NTO 4 /STO 4 ) 10 superlattice is shown in Fig.…”