A. M. Saletsky

Emergence of giant magnetic anisotropy in freestanding Au/Co nanowires

The emergence of giant magnetic anisotropy was found in evenly mixed Au/Co nanowires. First principles molecular dynamics calculations revealed the large values of magnetic anisotropy energy of about ∼130 meV per Co atom in Au/Co nanowires. It was established that the emergence of giant magnetic anisotropy is due to (dxy,dx2) band splitting caused by the strong spin-orbit interaction between gold and cobalt atoms in the wire. It is also shown that the energy of the magnetic anisotropy depends strongly on the geometry and composition of the wire.

Investigation of denaturation of human serum albumin under action of cethyltrimethylammonium bromide by raman spectroscopy

The mechanism of denaturation of human serum albumin (HSA) under action of a cationic detergent—cethyltrimethylammonium bromide (CTAB) is investigated by Raman spectroscopy method. The percentage contents of α-helical segments in polypeptide chain of HSA at denaturation under action of different concentrations of CTAB at different values of pH is determined. It is shown, that more intensive denaturation of HSA under action of CTAB takes place at pH values, larger the isoelectric point of protein (pI 4.7).

Simulation of the formation of vacancies upon scanning of Cu(100) surface

The main mechanisms of the formation of vacancies in the first layer of Cu(100) surface have been investigated by the molecular dynamics method. It has been shown that the interaction of the tip of a scanning tunneling microscope with the surface can increase the intensity of the formation of surface vacancies by a factor of 103−105. On the basis of the reported investigations, an effective method has been proposed for controlling the vacancy concentration in the first layer of Cu(100) surface, which does not imply a change in the temperature of the system.

Raman Spectroscopy in Investigations of Secondary Structure of Human Serum Albumin at Binding of Nanomarkers of Fluorescein Family

The influence of binding of nanomarkers of fluorescein family to HSA on secondary structure of this protein at different values of pH was investigated by Raman spectroscopy method. The greatest changes in secondary structure of HSA, consisting in decreasing of α-helix sites, at binding of fluorescein to HSA occur at pH 5–6. The greatest changes in secondary structure of HSA, consisting in decreasing of α-helix sites, at binding of eosin or erythrosin to HSA take place at values of pH, smaller 5. The differences in changes in secondary structure of HSA at binding of these three nanomarkers are explained by dependences of binding of nanomarkers to HSA on pH which determined by value of electronegativity of atoms of lateral radicals in structural formulas of nanomarkers and, therefore, by value of pK of their ionized groups.

Formation of gold nanocontacts in an ultrahigh vacuum transmission electron microscope: A kinetic Monte Carlo simulation

The effective method for the simulation of self-organization of metal nanocontacts produced in an ultrahigh vacuum transmission electron microscope has been designed. In the framework of this method the main stages of nanocontact formation have been determined. The basic diffusion events which are responsible for the shape of nanocontacts and the time of their formation have been outlined. The self-organization of nanocontacts with different orientation relative to the base fcc lattice has been studied. The results of our simulations are in a good agreement with experimental data.

Molecular dynamics simulation of the formation of metal nanocontacts

The process of the formation of nanocontacts has been studied by the molecular dynamics methods for a group of metals (Cu, Rh, Pd, Ag, Pt, Au). It has been shown that the disruption forces of nanocontacts substantially depend on the orientation ((100), (110), or (111)) of the contact-surface interface. The possibility of forming linear atomic chains as a result of the disruption of nanocontacts has been analyzed for different orientations of the electrode surfaces. The possibility of forming quasi-one-dimensional nanostructures from the Co/Au alloy, which represent a periodic alternation of gold atoms and cobalt trimers, has been predicted.

Effect of stretching-contraction deformations on the magnetic ordering state of mixed Pd-Fe nanowires

The performed ab initio calculations indicate the possibility of forming stable, uniformly mixed Pd-Fe nanowires. The effect of stretching-contraction deformations on the electronic structure of Pd-Fe nanowires has been revealed. Using the calculation results, a transition from ferromagnetic to antiferromagnetic state in a uniformly mixed Pd-Fe nanowire subjected to tension has been predicted.

Atomic and electronic structure of mixed Au-Co nanowires: Ab initio molecular dynamics study

The atomic and electronic structure of uniformly and nonuniformly mixed Au-Co nanowires have been studied using the ab initio molecular dynamics method. The effect of elastic stretching/contraction deformations on the stability and electronic properties of mixed Au-Co nanowires has been studied. It is established that Co dimers are formed in a nonuniformly mixed nanowire. The formation of CO2 dimers results in a non-uniform distribution of the electron density and interactomic distances along the wire and leads to accelerated rupture of the wire between Au atoms under stretching. Only a uniformly mixed Au-Co nanowire composed of regularly alternating Au and Co atoms is stable under stretching up to large interactomic distances.

Molecular Dynamics Study of the Mechanical Properties of Palladium Nanocontacts

The mechanical properties of extended palladium nanocontacts have been investigated by the molecular dynamics method. The characteristic interatomic distances in the contacts have been determined and the process of the formation of palladium atomic contacts undergoing breaking has been studied for the (100), (110), and (111) orientations of the contact-surface interfaces.

Magnetization dynamics of mixed Co–Au chains on Cu(110) substrate: Combined ab initio and kinetic Monte Carlo study*

We present an investigation of the one-dimensional ferromagnetism in Au–Co nanowires deposited on the Cu(110) surface. By using the density functional theory, the influence of the nonmagnetic copper substrate Cu(110) on the magnetic properties of the bimetallic Au–Co nanowires is studied. The results show the emergence of magnetic anisotropy in the supported Au–Co nanowires. The magnetic anisotropy energy has the same order of magnitude as the exchange interaction energy between Co atoms in the wire. Our electronic structure calculation reveals the emergence of new hybridized bands between Au and Co atoms and surface Cu atoms. The Curie temperature of the Au–Co wires is calculated by means of kinetic Monte Carlo simulation. The strong size effect of the Curie temperature is demonstrated.