V. V. Polyakov

Solid-state synthesis of the ZnO-Fe 3 O 4 nanocomposite: Structural and magnetic properties

The structural and magnetic properties of ZnO-Fe3O4 nanocomposites produced by the solid-state reaction Zn + 3Fe2O3 → ZnO + 2Fe3O4 upon annealing of Zn/α-Fe2O3 films under vacuum at a temperature of 450°C have been studied. Ferrimagnetic Fe3O4 clusters with an average grain size of 40 nm and a magnetization of ∼430 emu/cm3 at room temperature, which are surrounded by a ZnO layer with a large contact surface, have been synthesized. The magnetic characteristics of the ZnO-Fe3O4 nanocomposite in the temperature range of 10–300 K have been presented.

Magneto-optical properties of polycrystalline CoCrFeO4 films

A methods of obtaining polycrystalline CoCrFeO4 films based on solid-phase reactions in Cr2O3/Co/Fe layer structures in the regimes of isothermal annealing and self-propagating high-temperature synthesis (SHS) is described. The magneto-optical properties of the obtained films have been studied. It is established that the spectra of magneto-optical characteristics depend on the solid-phase reaction regime and synthesis temperature. The Faraday rotation angle exhibits a local maximum (2θF = 5 deg/μm) at a wave-length of 630 nm.

Evolution of the structure and magneto-optical properties of MnxFe3 − xO4 films prepared by solid-state reactions

This paper reports on the results of investigations into the structure and the magnetic and magnetooptical properties of thin films MnxFe3 − xO4 prepared by solid-state reactions: isothermal annealing, self-propagating high-temperature synthesis, and a combination of these two regimes. The regimes favorable for the formation of films close in composition and structure to the stoichiometric compounds MnFe2O4 or Fe3O4 are established. The features observed in the spectral response of the magneto-optical Faraday effect and of the magnetic circular dichroism of the MnFe2O4 films are considered in terms of the electronic transitions in magnetic ions, primarily Fe3+, which occupy octahedral positions in the spinel structure.

Magneto-optical properties of nanogranulated Co-Ti-O films

The results from studies of the magneto-optical properties of Co-Ti-O nanogranulated films obtained under conditions of solid-state reaction with oxygen exchange in CoO/Ti layered structures are presented. The magneto-optical spectra of the polar Kerr effect in films with a relative volume of the magnetic fraction of 0.38 to 0.64 has a resonance character in the wavelength range of 450–650 nm. The Kerr rotation angle of the films increases by a factor of 3–5, relative to conventional Co films.

Synthesis and magneto-optical properties of nanogranular Co-Ti-O films

Studies of the structural and magneto-optical properties of nanogranular Co-Ti-O films prepared under conditions of the solid-state reaction with oxygen exchange in the CoO/Ti layered structures are presented. The formation of granular films with compositions near or below the percolation threshold is shown. The specific features of the magneto-optical spectra of the prepared films as compared to the spectra of continuous metallic films are revealed.

Total cross sections for fission of heavy nuclei by intermediate-energy protons

The results of measuring total cross sections for proton-induced fission of natPb, 209Bi, 232Th, 233U, 235U, 238U, 237Np, and 239Pu nuclei at proton energies from 200 to 1000 MeV are reported. The measurements were carried out in steps of ≈100 MeV. Complementary fission fragments were detected in coincidence by two parallel-plate avalanche gas counters placed in the beam line on both sides of the thin target close to it. Energy and isotope dependences of the fission cross sections are analyzed.

Measurement of the spin rotation parameters R and A in πp elastic scattering and a test of πN partial-wave analyses in the region of low-lying P11, S11 and D13 resonances

Abstract This paper presents the results of an experiment in which the spin rotation parameters R and Ain π − p elastic scattering have been measured at energies 450, 530, 560 and 600 MeV. The experiment was performed on a pion channel of the PNPI synchrocyclotron. The main parts of the setup were a polarized proton target with horizontal spin orientation and a carbon-plate polarimeter consisting of multigap optical spark chambers with television read-out. A comparison of the obtained results with partial-wave analyses is given.

Magneto-Optical Properties of Co/TiO2 Layered Films

Spectral dependences of the polar Kerr effect in Co/TiO2 multilayer films in the spectral range 400--1000 nm have been studied. It is shown that the sign, value, and shape of the magneto-optical spectrum depend on the thickness of a dielectric spacer and the number of layers in the structure. It has been established that the magneto-optical rotation in the Co/TiO2 films considerably exceeds that in homogeneous Co films. The magneto-optical rotation attains the record value 2θk = 7.3 deg in the Co (5 nm)/ TiO2 (17 nm) layered structure with the number of layer pairs n = 8 at a wavelength of 560 nm.

Magnetic properties of polycrystalline films of CoCr2O4 and CoFe0.5Cr1.5O4 multiferroics

This paper reports on the first study of the magnetic properties of polycrystalline films of CoCr2O4 and CoFe0.5Cr1.5O4 multiferroics. The study covered, in particular, magnetization reversal curves and temperature dependences of the magnetization at temperatures ranging from 4.2 to 300 K in magnetic fields of up to 10 kOe. It has been shown that the Curie temperature and the pattern of the temperature dependence of the magnetization depend on the cation composition of the multiferroic. The temperature dependence of the magnetization of polycrystalline CoCr2O4 films has revealed an anomaly in the temperature range 10–70 K.

The enhanced magneto-optical Kerr effect in Co/TiO2 multilayer films

Spectral dependences of the polarization plane rotation angle (θk) in the polar Kerr effect in Co/TiO2 multilayer nanocomposite films have been studied in the 400–1000 nm wavelength range. It is established that the sign, magnitude, and shape of the magneto-optical spectrum depend on the dielectric spacer thickness and the number of layers in the structure. The Kerr rotation angle in Co/TiO2 multilayers is significantly greater than that in homogeneous Co films of the same thickness. The angle of rotation of the polarization plane reaches a record high value of 2θk = 7.3° in the Co(5 nm)/TiO2(17 nm) multilayer structure with number of layers n = 8 at a wavelength of 540 nm.