The ability of electron microscopes to analyze all the atoms in individual nanostructures is limited by lens aberrations. However, recent advances in aberration-correcting electron optics have led to greatly enhanced instrument performance and new techniques of electron microscopy. The development of an ultrastable electron microscope with aberration-correcting optics and a monochromated high-brightness source has significantly improved instrument resolution and contrast. In the present work, we report information transfer beyond 50 pm and show images of single gold atoms with a signal-to-noise ratio as large as 10. The instrument's new capabilities were exploited to detect a buried Sigma3 {112} grain boundary and observe the dynamic arrangements of single atoms and atom pairs with sub-angstrom resolution. These results mark an important step toward meeting the challenge of determining the three-dimensional atomic-scale structure of nanomaterials.

Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called “big-data” methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient image features in a specific example of BiFeO3 domains. Remarkably, k-means clustering reveals domain differentiation despite the fact that the algorithm is purely statistical in nature and does not require any prior information regarding the material, any coexisting phases, or any differentiating structures. While this is a somewhat trivial case, this example signifies the extraction of useful physical and structural information without any prior bias regarding the sample or the instrumental modality. Further interpretation of these types of results may still require human intervention. However, the open nature of this algorithm and its wide availability, enable broad collaborations and exploratory work necessary to enable efficient data analysis in electron microscopy.

The so-called proximity effect is the manifestation, across an interface, of the systematic competition between magnetic order and superconductivity. This phenomenon has been well documented and understood for conventional superconductors coupled with metallic ferromagnets; however it is still less known for oxide materials, where much higher critical temperatures are offered by copper oxide-based superconductors. Here we show that, even in the absence of direct Cu-O-Mn covalent bonding, the interfacial CuO 2 planes of superconducting La 1.85 Sr 0.15 CuO 4 thin films develop weak ferromagnetism associated to the charge transfer of spin-polarised electrons from the La 0.66 Sr 0.33 MnO 3 ferromagnet. Theoretical modelling confirms that this effect is general to all cuprate/manganite heterostructures and the presence of direct bonding only affects the strength of the coupling. The DzyaloshinskiiMoriya interaction, also at the origin of the weak ferromagnetism of bulk cuprates, propagates the magnetisation from the interface CuO 2 planes into the superconductor, eventually depressing its critical temperature.

The formation of a 2-dimensional electron liquid with tunable conductivity and superconductivity at the interface between band insulators SrTiO 3 (STO) and LaAlO 3 (LAO) [1] is an example of novel interface functionality with great potential for applications [2]. However, in spite of intense research efforts, the microscopic mechanism underlying such fascinating behavior is still controversial. A viable route to improve our understanding of STO/LAO interfaces is to investigate the properties of novel heterostructures realized with alternative overlayer materials. Alternative materials should be searched within wide band-gap insulating ABO 3 perovskites showing a high quality growth on STO and having trivalent cations both on the A and the B site. On the basis of such considerations, LaGaO 3 (LGO), a polar, wide band gap, pseudocubic perovskite, was selected and highly conducting interfaces were obtained in the LGO/STO system [3,4]. Although LAO/STO and LGO/STO show qualitatively similar transport properties, LGO/STO shows a slightly larger conductivity than LAO/STO (see Fig. 1a), independent of the oxygen pressure during growth. Here we use aberration corrected Z-contrast scanning transmission electron microscopy (Z-STEM) and atomically resolved electron energy loss spectroscopy (EELS) to gain insights into the similarities and differences between these two interface systems and their implications on the mechanism for electrical conductivity.