We report on the synthesis of unique tetragonal nanostructures from porous anodic aluminum oxide that enables geometrical three-dimensional (3D) microdesign of the porous surfaces. Scanning electron microscopy study revealed self-organization of hollow oxide nanostructures into hierarchical arrays. The formation of these structures has a localized nature and is associated with local electrical break-down during hard anodization of aluminum in oxalic acid solution. Moreover, in this communication we propose the mechanism of the nucleation and growth of complex 3D structures from porous anodic alumina.

Intense broad absorption bands centered around 1.7, 2.5, 3.1, and 3.7 eV take place in Er3+-diffused layer formed near MgO (5 mol%)-doped LiNbO3 crystal surface by in-diffusion of Er metal under Li-poor atmosphere. These bands are tentatively attributed to the defect absorption of small polarons, bipolarons, F-centers, and Q-polarons created due to Er3+ in-diffusion and Li2O loss from the crystal. It is interesting that the number, type, area, and peaking position of the bands can be controlled by the diffusion temperature and further oxidation treatment. Such material is a promising medium for data storage based upon two-color holography.

We study strain fields and deformation patterns produced by wedge indentation of metals using high-resolution imaging, image correlation and simulation. A long-standing problem associated with simulation of narrow angle wedge indentation is overcome by introducing a weak form of the symmetry boundary conditions. The simulated deformation fields show good agreement with experiment. Based on strain localization, three distinct modes of deformation largely cover the range of wedge angles. Importantly, narrow angle wedge indentation is characterized by intense strain localization at points close to the free surface and thus offers a possible new tool to probe strain gradient effects.

The ground-state structural, electronic, magnetic, optical and dielectric properties of MnTiO3 are calculated using density functional theory within the generalized gradient approximation. The structure parameters obtained agree well with experimental results. The electronic structure results show that the G-type antiferromagnetic phase of LN-type MnTiO3 has an indirect band gap of 0.85 eV. The calculated local magnetic moment of Mn ion is 4.19 μB. The calculated Born effective charges (BECs, denoted by tensor Z*) show that the Z* of Ti and O atoms are significantly and anomalously large. Interestingly, ferroelectric spontaneous polarization of large magnitude is predicted to be along [111] direction with a magnitude of 87.95–105.22 μC/cm2. B-site Ti ions in 3 d0 state dominate ferroelectric polarization of multiferroic MnTiO3, whereas A-site Mn ions having partially filled 3 d5 orbitals are considered to contribute to its antiferromagnetic properties. Furthermore, it is predicted that multiferroic MnTiO3 shows good dielectric and optical properties.

Organic–inorganic interfaces exist in many natural or synthetic materials, such as mineral–protein interfaces found in bone and epoxy–silica interfaces found in concrete construction. Here, we report a model to predict the intrinsic strength between organic and inorganic materials, based on a molecular dynamics simulation approach combined with the metadynamics method, used to reconstruct the free energy surface between attached and detached states of the bonded system and scaled up to incorporate it into a continuum model. We apply this technique to model an epoxy–silica system that primarily features nonbonded and nondirectional van der Waals and Coulombic chemical interactions. The intrinsic strength between epoxy and silica derived from the molecular level is used to predict the structural behavior of epoxy–silica interface at the macroscopic length scale by invoking a finite element approach using a cohesive zone model which shows a good agreement with existing experimental results.

Nanostructured Al–Mn alloys are proposed as high-strength low-density materials, which can be electroformed (i.e., produced electrolytically and removed from the substrate) from ionic liquid. A variety of current waveforms, including direct current (DC) and pulsed current (PC), are used to electrodeposit nanostructured Al–Mn alloys, with some PC methods producing significant improvements in film ductility. Transmission electron microscopy observations point to a number of structural advantages induced by PC that apparently ductilize the Al–Mn alloys: (i) grain refinement to the nanocrystalline range without the introduction of a competing amorphous phase, (ii) unimodal nanocrystalline grain size distribution, and (iii) more homogeneous structure. The significant increase in apparent ductility in the PC alloys is also apparently related to stress- or deformation-induced grain growth, which leads to alloys with unique combinations of specific hardness and film ductility.