A. Busiakiewicz

The role of water in resistive switching in graphene oxide

The resistive switching processes are investigated at the nano-scale in graphene oxide. The modification of the material resistivity is driven by the electrical stimulation with the tip of atomic force microscope. The presence of water in the atmosphere surrounding graphene oxide is found to be a necessary condition for the occurrence of the switching effect. In consequence, the switching is related to an electrochemical reduction. Presented results suggest that by changing the humidity level the in-plane resolution of data storage process can be controlled. These findings are essential when discussing the concept of graphene based resistive random access memories.

The new high-temperature surface structure on reduced TiO2(001)

Scanning tunnelling microscopy, ultraviolet photoelectron spectroscopy and current imaging tunnelling spectroscopy (STM/UPS/CITS) were used to study the topographic and electronic structure of a high-temperature structure formed on the TiO(2)(001) surface after heating at 1173 K. The STM images revealed different domain-like ordering and periodicity on the surface in comparison to those observed previously. The UPS studies showed the presence of a surface state at energy about 1.1 eV below the Fermi level. This result was confirmed by the CITS data showing pronounced periodic maxima of the electron local density of states at energy around 1.1-1.2 eV below the Fermi level and located on top of every row of the new high-temperature structure. The CITS results recorded for small grains, which coexist with the observed structure, showed that their chemical composition is closer to the Ti(2)O(3) material than to TiO(2-x) for x << 1.

Detection and analysis of spin signal in spin-labeled poly(l-lysine)

In this paper, the authors present the study of spin-labeled poly(l-lysine) biological molecules (polypeptides) using electron paramagnetic resonance, atomic force microscopy, and electron spin noise-scanning tunneling microscopy. In the presented studies, the authors were able to obtain the information about the local distribution of the spin signal emission, and they registered the spectra for the selected area with nanometer resolution. The preparation method of spin-labeled biopolymer, experimental setup, and the procedure of calibration are also described in detail.

Temperature-induced segregation of Co- and Ni-rich nanoparticles on rutile TiO2(001)

Cobalt- and nickel-rich nanoparticles were produced by direct segregation from a single crystal rutile TiO2 in ultra-high vacuum conditions. It was shown that, similarly to the previous findings for Fe, also in the case of Co and Ni, the segregation of a noticeable amount of material is possible on the (001) surface. Segregation of these metals results in formation of nanoparticles and their distribution on the surface partially reflects the substrate symmetry in the case of Co and reveals some signs of self-organization for Ni. Cyclic appearance and disappearance of Co- and Ni-rich nanoparticles can be fully controlled by the temperature of annealing. The explanation of the mechanism of repeatable segregation is proposed basing on interaction of Co and Ni cations with Ti interstitials. These new findings can be especially important for catalysis and spintronic applications where the controlled nanoparticles size and concentration are crucial.