V. R. Galakhov

Bio: V. R. Galakhov is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Absorption spectroscopy & Emission spectrum. The author has an hindex of 20, co-authored 120 publications receiving 1585 citations. Previous affiliations of V. R. Galakhov include Ural State Mining University & Ural Federal University.

Mn 3s exchange splitting in mixed-valence manganites.

Abstract: We present Mn $3s$ x-ray photoelectron spectra of manganese oxides with the Mn formal valency from $2+$ to $4+.$ We found that the ${\mathrm{Sr}}^{2+}$ doping or cation deficiency in manganites do not change the Mn $3s$ splitting in manganites with the Mn formal valency from $3.0+$ to $3.3+.$ We suggest that doping holes are localized in O $2p$ states.

Valence-band spectra and electronic structure of CuFeO 2

Abstract: The delafossite-type ${\mathrm{CuFeO}}_{2}$ single crystal was studied by means of x-ray emission and x-ray photoelectron spectroscopy. The valence state of Cu ions was found to be $1+,$ whereas Fe ions were found to be trivalent in the high-spin $S=5/2$ state. The x-ray emission (Cu ${L}_{\ensuremath{\alpha}},$ Fe ${L}_{\ensuremath{\alpha}},$ and O ${K}_{\ensuremath{\alpha}})$ and photoelectron spectra were compared to the results of the local spin density approximation (LSDA) (full-potential linearized augmented plane wave method and linearized muffin-tin orbitals in atomic sphere approximation method) and $\mathrm{LSDA}+U$ calculations. It is found that the maximum of the Cu $3d$ state distribution is localized closer to the Fermi level than that of the Fe $3d$ states. The LSDA calculations contradict the experimental results and do not give a correct description of the Cu and Fe $3d$ positions relative to the Fermi level, and incorrectly predict metallic behaviors (semiconductor observed) and give qualitatively incorrect magnetic properties of ${\mathrm{CuFeO}}_{2}.$ The $\mathrm{LSDA}+U$ calculations give a much better agreement with the observed valence-band structure, the measured electrical, and the magnetic properties.

Photoemission study of the metal-insulator transition in CuIr 2 S 4

Abstract: We have studied the electronic structure and its changes across the metal-insulator transition in the spinel-type compound ${\mathrm{CuIr}}_{2}$${\mathrm{S}}_{4}$ using photoemission and inverse-photoemission spectroscopy. Photoemission spectra near the Fermi level show a gap opening of \ensuremath{\sim}20 meV in the insulating phase, consistent with the transport activation energy. Core-level spectra indicate that the Cu ion is monovalent, and hence Ir is in the intermediate valence state of +3.5. Comparison between the spectra and band-structure calculation reveals that the Ir 5d density of states is strongly distorted, probably due to electron correlation in spite of the general belief of weak correlation in 5d-electron systems.

Electronic structure, x-ray spectra, and magnetic properties of the LiCoO2−δ and NaxCoO2 nonstoichiometric oxides

Abstract: This paper reports on a study of the magnetic susceptibility, x-ray photoelectron, and x-ray emission spectra of the LiCoO2−δ and NaxCoO2 nonstoichiometric oxides. The valence-band structure of LiCoO2 was analyzed. The hole concentration in the oxygen 2p band of LiNiO2 and LiCoO2 was derived from measurements of the O Kα emission spectra. Measurements of Co 2p and Co 3s photoelectron spectra showed that the Co3+ ions reside in the low-spin state with S=0. The deficiency of oxygen in the LiCoO2−δ reduced oxides gives rise to the formation of divalent cobalt ions. The deficiency of the alkali metal in NaxCoO2 initiates the formation of holes in the oxygen 2p band while not changing the electronic configuration d 6 of the cobalt-ion ground state.

Valence states of copper ions and electronic structure of LiCu 2 O 2

Abstract: The electronic structure of LiCu${}_{2}$O${}_{2}$ was studied using x-ray emission (Cu ${L}_{\ensuremath{\alpha}},$ O ${K}_{\ensuremath{\alpha}})$ and photoelectron spectroscopy (valence band and core levels) as well as band-structure calculations in terms of local spin-density approximation (LSDA) and LSDA+$U$ approaches. According to the x-ray-emission and photoelectron spectra the valence states of the Cu atoms are found to be mixed, i.e., 2+ and 1+. The LSDA calculations are contradictory to the experimental data and cannot reproduce the band gap and magnetic properties of ${\mathrm{LiCu}}_{2}{\mathrm{O}}_{2}$. The LSDA+$U$ calculations describe the insulator and antiferromagnetic properties much better but the overestimation of the screened Coulomb parameter $U$ leads to a binding-energy shift of the Cu${}^{\mathrm{II}}$ $3d$ states and this distorts the proper modeling of the valence-band structure. The magnetic structure of LiCu${}_{2}$O${}_{2}$ is discussed, taking our LSDA+$U$ band-structure calculations into account.

Nickel‐Rich Layered Lithium Transition‐Metal Oxide for High‐Energy Lithium‐Ion Batteries

Abstract: High energy-density lithium-ion batteries are in demand for portable electronic devices and electrical vehicles. Since the energy density of the batteries relies heavily on the cathode material used, major research efforts have been made to develop alternative cathode materials with a higher degree of lithium utilization and specific energy density. In particular, layered, Ni-rich, lithium transition-metal oxides can deliver higher capacity at lower cost than the conventional LiCoO2 . However, for these Ni-rich compounds there are still several problems associated with their cycle life, thermal stability, and safety. Herein the performance enhancement of Ni-rich cathode materials through structure tuning or interface engineering is summarized. The underlying mechanisms and remaining challenges will also be discussed.

Resonant Inelastic X-ray Scattering Studies of Elementary Excitations

Abstract: Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

31p-S-4 Giant Magnetoresistance in Magnetic Manganese Oxide with Intrinsic Antiferromagnetic Spin Structure

Abstract: Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin‐dependent electron scattering due to spin canting of the manganese oxide.

An international symposium

Abstract: s should clearly state the purpose, brief statement of procedure, results and conclusions. Please include your name, full address and topic on all submissions. At least one author of each abstract should register for the conference. All accepted abstracts will be published as symposium proceedings. Additionally, commended abstracts may be published in a journal after they are expanded to a manuscript followed by extensive reviewing. The language of the conference will be English.