The single-phase multiferroic compound Pb(Fe0.5Nb0.5)O3 (PFN) is a good candidate for new nanoscale technologies; however, studies have focused mostly on PFN ceramics and little has been published about thin films. In this work, we are reporting the local ferroelectric and piezoelectric properties of highly textured [110]-oriented PFN thin films grown by rf-magnetron sputtering on SrRuO3/SiOx/Si substrates, and the strong correlation existing with the crystalline structure. The crystallographic study was realized using X-ray diffraction with monochromatic CuKα radiation and by high-resolution transmission electron microscopy. Piezoresponse force microscopy (PFM) was used to determine out-of-plane and in-plane surface topography, ferroelectric domain structure, domain switching and ferroelectric hysteresis of as deposited PFN films. Using structural simulation and the surface representation of the piezoelectric tensor, the observed domain patterns are explained in terms of a complex configuration of 70º, 109º, and 180º domain walls, where the domains with out-of-plane <110> and/or <1-10> preferential orientations are connected through crystalline faces or edges. After poling with an optimal applied dc bias, sharp images of up-down domain switching, using PFM in resonance mode, are presented. A piezoelectric constant d33 of 10 pm/V and a coercive electric field of ~388 kV/cm (4.65 V) were calculated from local hysteresis loops.
This work was supported by PAPIIT-DGAPA-UNAM (Grants IN110315 and IN105317) and CONACYT (Grants Fronteras-2026, 282778 and 280309). Technical assistance from E. Aparicio, F. Ruiz, I. Gradilla, P. Casillas, and E. Murillo is duly acknowledged.