We examine the phenomenon of flexoelectric switching of polarization in ultrathin films of barium titanate induced by a tip of an atomic force microscope (AFM). The spatial distribution of the tipinduced flexoelectricity is computationally modelled both for perpendicular mechanical load (point measurements) and for sliding load (scanning measurements), and compared with experiments. We find that (i) perpendicular load does not lead to stable ferroelectric switching in contrast to the load applied in the sliding contact load regime, due to non-trivial differences between the strain distributions in both regimes: ferroelectric switching for the perpendicular load mode is impaired by a strain gradient inversion layer immediately underneath the AFM tip; while for the sliding load regime, domain inversion is unimpaired within a greater material volume subjected to larger values of the mechanically induced electric field that includes the region behind the sliding tip; (ii) beyond a relatively small value of an applied force, increasing mechanical pressure does not increase the flexoelectric field inside the film, but results instead in a growing volume of the region subjected to such field that aids domain nucleation processes; and (iii) the flexoelectric coefficients of the films are of the order of few nC/m, which is much smaller than for bulk BaTiO 3 ceramics, indicating that there is a "flexoelectric size effect" that mirrors the ferroelectric one.

The photoelectrochemical properties of template-engineered epitaxial BiVO4 photoanodes have been enhanced approximately 10 times that of bare BiVO4.

Understanding new superconductors requires high-quality epitaxial thin films to explore intrinsic electromagnetic properties, control grain boundaries and strain effects, and evaluate device applications 1-9 . So far superconducting properties of ferropnictide thin films appear compromised by imperfect epitaxial growth and poor connectivity of the superconducting phase 10-14 . Here we report novel template engineering using single-crystal intermediate layers of (001) SrTiO 3 and BaTiO 3 grown on various perovskite substrates that enables genuine epitaxial films of Co-doped BaFe 2 As 2 with high transition temperature (T c , ρ=0 of 21.5K), small transition widths (∆T c = 1.3K), superior J c of 4.5 MA/cm 2 (4.2K, self field) and strong c-axis flux pinning. Implementing SrTiO 3 or BaTiO 3 templates to match the alkaline earth layer in the Ba-122 with the alkaline earth-oxygen layer in the templates opens new avenues for epitaxial growth of ferropnictides on multi-