Recent studies have produced 0.1 × 0.1 μm ferroelectric cells in both bismuth titanate and strontium bismuth tantalate, thus taking thin-film ferroelectric memories into the regime of nanoscale (100 nm or less) devices. A review is presented of deposition, switching, and leakage current in these devices, which are small enough to permit 1 Gbit memories on a standard Si chip.

We report a large photovoltaic (PV) effect in multiferroic ${\text{Bi}}_2{\text{FeCrO}}_6$ (BFCO) films under monochromatic illumination at 635 nm with an intensity of $1.5\text{mW}{\text{cm}}^{-2}$ . These multiferroic films exhibit a large photocurrent at zero bias voltage and an open-circuit voltage of about 0.6 V. A high PV power conversion efficiency of about 6% for red light is achieved and attributed to a high degree of B-site cationic ordering between Fe and Cr sublattices, the tuning of which is likely to play a key role in further improvements of the PV properties in BFCO.

A study of the frequency dependence of the signal in piezoresponse scanning force microscopy of ferroelectric materials has been performed. It is found that, for soft cantilevers, the signal is governed by the cantilever elastic properties. Both ferroelectric-electromechanical and electrostatic interaction contributions to the overall signal were found to depend on the frequency of the testing voltage. Indications for optimal measurement regimes are given.

In this letter, we report on the switching properties of an ordered system of ${\mathrm{Bi}}_{\mathrm{4}}{\mathrm{Ti}}_{\mathrm{3}}{\mathrm{O}}_{\mathrm{12}}$ ferroelectric memory cells of an average lateral size of 0.18 μm formed via a self-assembling process. The ferroelectricity of these cells has been measured microscopically and it has been demonstrated that an individual cell of 0.18 μm size is switching. Switching of single nanoelectrode cells was achieved via scanning force microscopy working in piezoresponse mode.

The authors report the structural and physical properties of epitaxial ${\mathrm{Bi}}_2\mathrm{Fe}\mathrm{Cr}{\mathrm{O}}_6$ thin films on epitaxial $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_3$ grown on (100)-oriented $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ substrates by pulsed laser ablation. The $300\mathrm{nm}$ thick films exhibit both ferroelectricity and magnetism at room temperature with a maximum dielectric polarization of $2.8\mu \mathrm{C}∕{\mathrm{cm}}^2$ at $E_{\max }=82\mathrm{kV}∕\mathrm{cm}$ and a saturated magnetization of $20\mathrm{emu}∕{\mathrm{cm}}^3$ (corresponding to $\sim 0.26\mu B$ per rhombohedral unit cell), with coercive fields below $100\mathrm{Oe}$ . The results confirm the predictions made using ab initio calculations about the existence of multiferroic properties in ${\mathrm{Bi}}_2\mathrm{Fe}\mathrm{Cr}{\mathrm{O}}_6$ .