Retention loss behaviors in heteroepitaxial ferroelectric film with a +c monodomain fabricated by hydrothermal epitaxy below Tc

Abstract

We observed the retention loss of dot domains ͑36 nm diameter͒ and square domains with sizes of 1 and 25 m 2 that were reversed by applying an electric field at an atomic force microscopy ͑AFM͒ conductive tip on a heteroepitaxial PbTiO 3 thin film with ϩ polarization in the virgin state, which was fabricated via hydrothermal epitaxy below T c . Through theoretical calculations, it was discussed that the retention loss phenomena of a domain reversed by using an AFM tip were derived from the summation of the depolarization field energy and the strain-polarization coupling energy. Since the retention loss of the reversed domain with a straight c / c domain wall by applying a homogeneous electric field did not occur, we suggest that a cylindrical domain, which has a nearly straight c / c domain wall that extends to the bottom electrode on the given thin film, would be free from the retention loss.

Boehmite nanoparticles incorporated electrospun nylon-6 nanofiber web for new electret filter media

“…Ahn et al obtained high efficiency filter media with PA6 nanofiber web which showed 99.993% of efficiency and 150 mmH 2 O of resistance at 5 cm/s of face velocity and 0.3 µm of PSL particles as a challenging aerosol. 16 Their nanofiber web showed 0.064 mmH 2 O -1 and a filtration index similar conditions to our study. This comparison indicates that PA6 nanofiber web produced in this study is very promising to develop high efficiency filter media without sacrificing the resistance.…”

“…The filtration performance of nanofiber filter media has been evaluated by various kinds of challenging aerosols such as NaCl, 6 silver, 6 polystyrene latex (PSL) 6,16 and ISO fine test dust 2 at different flow rates. Ahn et al obtained high efficiency filter media with PA6 nanofiber web which showed 99.993% of efficiency and 150 mmH 2 O of resistance at 5 cm/s of face velocity and 0.3 µm of PSL particles as a challenging aerosol.…”

Hydrothermally fabricated epitaxial PbTiO3 patterns patterned lithographically by etching in hydrothermal KOH solution

“…It is suggested that the free energy increment due to the depolarization field energy at a curved c / c domain wall is enough to initiate the lateral movement of the curved c / c domain wall. 11 However, in our case, the dot domain with a doubleparabolic or inverted semi-ellipsoid-shaped c / c domain wall, as in the plot 1 of Fig. 3͑f͒, did not show retention loss phenomena despite being in the etching solution for a period of 12 h. Schwarzkopf et al 14 reported that less surface effect owing to less space charge causes long data retention.…”

“…Details of the measurement can be found elsewhere. 10,11 In PbTiO 3 crystal films, etching behaviors have not yet been analyzed. Figures 1͑a͒-1͑c͒ show the schematics illustrating the flow chart of processes involved in the fabrication of selective patterning in PbTiO 3 with KOH wet etching using a SPM cantilever tip.…”

“…Dot domains that are not fully reversed and that lack enough time to invert domains will have a parabolic domain wall. 11 While etching the films using KOH solution, the +Z face was etched whereas the −Z face remained unetched as can be seen in the SEM images in Figs can be used to fabricate nanoscale surface patterns. 5,6 Perovskite PbTiO 3 ferroelectric materials have the characteristic property of ionic displacement type polarization.…”