Two‐variant stripe domains in BiFeO3 films on miscut (001) SrTiO3 substrates exhibit square‐like, complete ferroelectric switching with low leakage current. Both the preferential distortion of BiFeO3 unit cells and the persistent step‐flow growth induced by the substrate anisotropy are the origins of the formation of the two‐variant stripe domains in (001) BiFeO3 films.

Direct measurement of the remanent polarization of high quality (001)-oriented epitaxial BiFeO3 thin films shows a strong strain dependence, even larger than conventional (001)-oriented PbTiO3 films. Thermodynamic analysis reveals that a strain-induced polarization rotation mechanism is responsible for the large change in the out-of-plane polarization of (001) BiFeO3 with biaxial strain while the spontaneous polarization itself remains almost constant.

We report substantially reduced fatigue and electrical leakage in BiFeO3 membranes fabricated by releasing epitaxial (001) BiFeO3 films from the Si substrates on which they were grown. Fatigue-free switching behavior of up to 1010cycles was observed for BiFeO3 membranes with Pt top electrodes, while as-grown films break down at ∼109cycles. This is attributed to the low coercive field of BiFeO3 membranes and their being free from substrate clamping. In contrast, (111) BiFeO3 films exhibit significant fatigue at the same electric field. Epitaxial (001) BiFeO3 membranes with low coercive field are very promising for lead-free ferroelectric memory and magnetoelectric devices.

Background Access site hematomas and pseudoaneurysms are the most frequent complications of peripheral vascular intervention (PVI); however, their incidence and risk factors remain unclear. Methods and Results We retrospectively analyzed data from the multicenter Vascular Quality Initiative® on 22,226 patients who underwent 27,048 PVI from August 2007 to May 2013. Primary endpoints included incidence and predictors of access site complications (ASC), length of postprocedural hospitalization, discharge status, and 30-day and 1-year mortality. ASC complicated 936 procedures (3.5%). Of these, 74.4% were minor complications, 9.7% were moderate requiring transfusion, 5.4% were moderate requiring thrombin injection, and 10.5% were severe requiring surgery. Predictors of ASC were age >75 years, female gender, white race, no prior PVI, nonfemoral arterial access site, >6-Fr sheath size, thrombolytics, arterial dissection, fluoroscopy time >30 minutes, nonuse of vascular closure device, bedridden preoperative ambulatory status, and urgent indication. Mean hospitalization was longer after procedures complicated by ASC (1.2 ± 1.6 days vs. 1.9 ± 1.9 days; range 0-7 days; p=0.002). Severity of ASC correlated with higher rates of discharge to rehabilitation/nursing facilities compared to home discharge. Patients with severe ASC had higher 30-day mortality (6.1% vs. 1.4%; p<0.001), and those with moderate ASC requiring transfusion had elevated 1-year mortality (12.1%, vs. 5.7%; p<0.001). Conclusions Several factors independently predict access site complication following peripheral vascular intervention. Appropriate use of antithrombotic therapies and vascular closure device in patients at increased risk of ASC may improve post-PVI outcomes.