Igor Zobkalo
@pnpi.nrcki.ru
Condensed Matter Research Department
Petersburg Nuclear Physics Institute
RESEARCH INTERESTS
Neutron scattering, multiferroics, polarized neutron diffraction
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
A.N. Matveeva, I.A. Zobkalo, A. Sazonov, A.L. Freidman, S.V. Semenov, M.I. Kolkov, K. Yu Terentjev, N.S. Pavlovskiy, K.A. Shaykhutdinov, and V. Hutanu
Elsevier BV
A. N. Matveeva, I. A. Zobkalo, and A. G. Pshenichnaia
Allerton Press
A.N. Matveeva, I.A. Zobkalo, M. Meven, A.L. Freidman, S.V. Semenov, K. Yu. K. Terentjev, N.S. Pavlovskiy, M.I. Kolkov, K.A. Shaykhutdinov, and V. Hutanu
Elsevier BV
O. V. Usmanov, A. K. Ovsianikov, I. A. Zobkalo, K. A. Shaykhutdinov, K. Yu. Terentjev, and S. V. Semenov
Pleiades Publishing Ltd
A.K. Ovsianikov, O.V. Usmanov, I.A. Zobkalo, W. Schmidt, A. Maity, V. Hutanu, E. Ressouche, K.A. Shaykhutdinov, K. Yu Terentjev, S.V. Semenov,et al.
Elsevier BV
A.K. Ovsianikov, O.V. Usmanov, I.A. Zobkalo, V. Hutanu, S.N. Barilo, N.A. Liubachko, K.A. Shaykhutdinov, K. Yu Terentjev, S.V. Semenov, T. Chatterji,et al.
Elsevier BV
S. Mansouri, M. Balli, S. Jandl, A. O. Suleiman, P. Fournier, M. Orlita, I. A. Zobkalo, S. N. Barilo, and M. Chaker
American Physical Society (APS)
Tatsiana Shulha, M. Serdechnova, M.H. Iuzviuk, I.A. Zobkalo, P. Karlova, N. Scharnagl, D.C.F. Wieland, S.V. Lamaka, A.A. Yaremchenko, C. Blawert,et al.
Elsevier BV
Igor Zobkalo, Sergey Gavrilov, Anna Matveeva, Andrew Sazonov, Sergey Barilo, Sergey Shiryaev, and Vladimir Hutanu
Institute of Electrical and Electronics Engineers (IEEE)
Neutron diffraction study of Nd<sub>0.8</sub>Tb<sub>0.2</sub>Mn<sub>2</sub>O<sub>5</sub> single crystal has been performed using both non-polarized and polarized neutron diffraction. Low temperature set of magnetic satellites corresponding to two magnetic ordered phases witnesses about the magnetic phase separation. One of those phases with propagation vector <inline-formula> <tex-math notation="LaTeX">$k_{1} = (0.5\\,\\,0\\,\\,k_{z1})$ </tex-math></inline-formula> bears features of magnetic order in TbMn<sub>2</sub>O<sub>5</sub> with ordering temperature <inline-formula> <tex-math notation="LaTeX">$\\text {TN} \\approx 37$ </tex-math></inline-formula> K. Another one with propagation vector <inline-formula> <tex-math notation="LaTeX">$k_{2} = (0.5\\,\\,0\\,\\,k_{z2})$ </tex-math></inline-formula> and Neel temperature of <inline-formula> <tex-math notation="LaTeX">$\\text {TN2} \\approx 30$ </tex-math></inline-formula> K has a great similarity to magnetic order of NdMn<sub>2</sub>O<sub>5</sub>. Both of them are chiral at low temperatures. Difference in chiral domain population could be controlled by the external electric field of few kV/cm. Two additional magnetic phases with <inline-formula> <tex-math notation="LaTeX">$k_{3,4} = (0.5\\,\\,0\\,\\,k_{z3,4})$ </tex-math></inline-formula> were observed in the short intermediate temperature range 20–28 K. Significant temperature hysteresis of 6–8 K for all magnetic phases was observed in dependence of cooling/heating temperature evolution. Results are discussed in the frame of competing magnetic interactions.
A. C. Bouali, M. H. Iuzviuk, M. Serdechnova, K. A. Yasakau, D. Drozdenko, A. Lutz, K. Fekete, G. Dovzhenko, D. C. F. Wieland, H. Terryn,et al.
American Chemical Society (ACS)
The growth of ZnAl layered double hydroxide (LDH) on the AA2024 surface was monitored using synchrotron high-resolution X-ray diffraction. Kinetic data were extracted and analysed using the Avrami Erofe’ev kinetic model. Accordingly, the LDH film growth is governed by a 2D diffusion-controlled reaction with a zero-nucleation rate. Additional methods including exsitu AFM/SKPFM supported by in-situ OCP measurements together with SEM and TEM/EDX analysis, provided further insight into the different stages of the mechanism of LDH growth. Prior to the conversion coating formation, an intermediate layer is formed as a basis for the establishment of the LDH flakes. Moreover, a Cu-rich layer was revealed, which could contribute to the acceleration of LDH growth. The formed LDH layer does not show any cracks
I. A. Zobkalo
Pleiades Publishing Ltd
Mariia H. Iuzviuk, Anissa C. Bouali, Maria Serdechnova, Kiryl A. Yasakau, D. C. Florian Wieland, Gleb Dovzhenko, Aliaksandr Mikhailau, Carsten Blawert, Igor A. Zobkalo, Mario G. S. Ferreira,et al.
Royal Society of Chemistry (RSC)
The first kinetic study of the anion exchange reactions on LDH conversion layers, with corrosion relevant species.
A.K. Ovsyanikov, I.A. Zobkalo, W. Schmidt, S.N. Barilo, S.A. Guretskii, and V. Hutanu
Elsevier BV
I. A. Zobkalo, A. N. Matveeva, A. Sazonov, S. N. Barilo, S. V. Shiryaev, B. Pedersen, and V. Hutanu
American Physical Society (APS)
Detailed investigation of the incommensurate magnetic ordering in a single crystal of multiferroic NdMn2O5 has been performed using both non-polarized and polarized neutron diffraction techniques. Below TN = 30.5 K magnetic Bragg reflections corresponding to the non-chiral type magnetic structure with propagation vector k1 = (0.5 0 kz1) occurs. Below about 27 K a new distorted magnetic modulation with a similar vector kz2 occurs, which is attributed to the magnetization of the Nd3+ ions by the Mn-sub-lattice. Strong temperature hysteresis in the occurrence of the incommensurate magnetic phases in NdMn2O5 was observed depending on the cooling or heating history of the sample. Below about 20 K the magnetic structure became of a chiral type. From spherical neutron polarimetry measurements, the resulting low-temperature magnetic structure kz3 was approximated by the general elliptic helix. The parameters of the magnetic helix-like ellipticity and helical plane orientation in regard to the crystal structure were determined. A reorientation of the helix occurs at an intermediate temperature between 4 K and 18 K. A difference between the population of right- and left-handed chiral domains of about 0.2 was observed in the as-grown crystal when cooling without an external electric field. The magnetic chiral ratio can be changed by the application of an external electric field of a few kV/cm, revealing strong magnetoelectric coupling. A linear dependence of the magnetic chirality on the applied electric field in NdMn2O5 was found. The results are discussed within the frame of the antisymmetric super-exchange model for Dzyaloshinsky-Moria interaction.
Anissa C. Bouali, Mariia H. Iuzviuk, Maria Serdechnova, Kiryl A. Yasakau, D.C. Florian Wieland, Gleb Dovzhenko, Hanna Maltanava, Igor A. Zobkalo, Mario G.S. Ferreira, and Mikhail L. Zheludkevich
Elsevier BV
Maria Serdechnova, Sergey Karpushenkov, Larisa Karpushenkava, Maksim Starykevich, Mario Ferreira, Theodor Hack, Mariia Iuzviuk, Igor Zobkalo, Carsten Blawert, and Mikhail Zheludkevich
MDPI AG
In the frame of the current work, it was shown that plasma electrolytic oxidation (PEO) treatment can be applied on top of phosphoric sulfuric acid (PSA) anodized aluminum alloy AA2024. Being hard and well-adherent to the substrate, PEO layers improve both corrosion and wear resistance of the material. To facilitate PEO formation and achieve a dense layer, the systematic analysis of PEO layer formation on the preliminary PSA anodized layer was performed in this work. The microstructure, morphology, and composition of formed PEO coatings were investigated using scanning electron microscopy (SEM), x-ray diffraction (XRD), and glow-discharge optical emission spectroscopy (GDOES). It was shown that under constant current treatment conditions, the PSA layer survived under the applied voltage of 350 V, whilst 400 V was an intermediate stage; and under 450 V, the PSA layer was fully converted after 5 min of the treatment. The comparison test with PEO formation on the bare material was performed. It was confirmed that during the “sparking” mode (400 V) of PEO formation, the PEO coatings, formed on PSA treated AA2024, were more wear resistant than the same PEO coatings on bare AA2024.
S. Mansouri, S. Jandl, M. Balli, P. Fournier, B. Roberge, M. Orlita, I. A. Zobkalo, S. N. Barilo, and S. V. Shiryaev
American Physical Society (APS)
Raman and infrared spectroscopies are used as local probes to study the dynamics of the Nd-O bonds in the weakly multiferroic ${\\mathrm{NdMn}}_{2}{\\mathrm{O}}_{5}$ system. The temperature dependence of selected Raman excitations reveals the splitting of the Nd-O bonds in ${\\mathrm{NdMn}}_{2}{\\mathrm{O}}_{5}$. The ${\\mathrm{Nd}}^{3+}$ ion crystal field (CF) excitations in ${\\mathrm{NdMn}}_{2}{\\mathrm{O}}_{5}$ single crystals are studied by infrared transmission as a function of temperature, in the $1800\\ensuremath{-}8000\\phantom{\\rule{0.16em}{0ex}}{\\mathrm{cm}}^{\\ensuremath{-}1}$ range, and under an applied magnetic field up to 11 T. The frequencies of all ${}^{4}{I}_{j}$ CF levels of ${\\mathrm{Nd}}^{3+}$ are determined. We find that the degeneracy of the ground-state Kramers doublet is lifted (${\\mathrm{\\ensuremath{\\Delta}}}_{0}\\ensuremath{\\sim}7.5\\phantom{\\rule{4pt}{0ex}}{\\mathrm{cm}}^{\\ensuremath{-}1}$) due to the ${\\mathrm{Nd}}^{3+}\\text{\\ensuremath{-}}{\\mathrm{Mn}}^{3+}$ interaction in the ferroelectric phase, below ${T}_{C}\\ensuremath{\\sim}28\\phantom{\\rule{0.16em}{0ex}}\\mathrm{K}$. The ${\\mathrm{Nd}}^{3+}$ magnetic moment ${m}_{\\mathrm{Nd}}(T)$ and its contribution to the magnetic susceptibility and the specific heat are evaluated from ${\\mathrm{\\ensuremath{\\Delta}}}_{0}(T)$ indicating that the ${\\mathrm{Nd}}^{3+}$ ions are involved in the magnetic and the ferroelectric ordering observed below $\\ensuremath{\\sim}28\\phantom{\\rule{0.16em}{0ex}}\\mathrm{K}$. The Zeeman splitting of the excited CF levels of the ${\\mathrm{Nd}}^{3+}$ ions at low temperature is also analyzed.
I A Zobkalo, S V Gavrilov, A Sazonov, and V Hutanu
IOP Publishing
In order to make a new approach to the elucidation of the microscopic mechanisms of multiferroicity in the RMn2O5 family, experiments with different methods of polarized neutrons scattering were performed on a TbMn2O5 single crystal. We employed three different techniques of polarized neutron diffraction without the analysis after scattering, the XYZ-polarization analysis, and technique of spherical neutron polarimetry (SNP). Measurements with SNP were undertaken both with and without external electric field. A characteristic difference in the population of ‘right’ and ‘left’ helix domains in all magnetically ordered phases of TbMn2O5, was observed. This difference can be controlled by an external electric field in the field-cooled mode. The analysis of the results gives an evidence that antisymmetric Dzyaloshinsky-Moria exchange is effective in all the magnetic phases in TbMn2O5.
I Zobkalo, S Gavrilov, V Matveev, and J Fenske
IOP Publishing
The project of a considerable modernization of the polarized neutron diffractometer POLDI is discussed. It assumes the adoption of POLDI to a broader range of magnetic investigations such as determination of magnetic structures, detailed investigation of complex magnetic structures, studies of magnetic domains, study of the magnetization density maps, magnetic form-factor particularities, local susceptibility, etc. The flexible construction should permit to use either spherical neutron polarimetry technique or flipping ratio technique. Different types of polarization system were analyzed. Original focusing fan-like bender is proposed as polarizer unit. Our simulations give evidence that for the wavelength range 1.3 - 3 Å and with suitable size, such a device can give much better efficiency than 3He cells, which are often in use. The higher flux at the sample position of a factor of at least 3.3, with lower divergence and good polarization degree from 98% (1.3 Å) to above 94% (3 Å) makes the bender set-up favorable over the layout with a 3He-cell.
A. A. Bykov, I. A. Zobkalo, A. A. Dubrovskii, O. P. Smirnov, S. E. Nikitin, K. Yu. Terent’ev, S. V. Gavrilov, and K. A. Shaikhutdinov
Pleiades Publishing Ltd
I. A. Zobkalo, S. V. Gavrilov, E. K. Dimakova, E. I. Golovenchic, and V. A. Sanina
Pleiades Publishing Ltd
I. A. Zobkalo, S. V. Gavrilov, V. A. Sanina, and E. I. Golovenchits
Pleiades Publishing Ltd
I.A. Zobkalo, S.V. Gavrilov, N.Z. Saw Nyi, S.N. Barilo, and S.V. Shiryaev
Elsevier BV
A.K. Ovsyanikov, I.V. Golosovsky, I.A. Zobkalo, and I. Mirebeau
Elsevier BV
A. Krimmel, I. Zobkalo, J. Schweizer, and A. Loidl
Elsevier BV