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Bezmaternykh, L. N.

Publications and source records attributed to Bezmaternykh, L. N..

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Magnetic properties of Co{sub 2}{sup 2+}Co{sub 1−} {sub x}{sup 3+}Fe{sub x}{sup 3+}BO{sub 5} (x = 0.10) single crystals with a ludwigite structure

The investigation of mixed Co–Fe ludwigite single crystals shows that their magnetic properties are close to the magnetic properties of Fe{sub 3}BO{sub 5} despite the predominance of cobalt ions. The magnetic properties of Co{sub 3–} {sub x}Fe{sub x}BO{sub 5} single crystals with x = 0.10 are studied in detail. Magnetometric measurements demonstrate a strong magnetic anisotropy with easy magnetization axis b, and the orbital magnetic moment of cobalt is in a frozen state. The detected temperature dependence of the absorption of Mössbauer spectra allowed us to determine the magnetic ordering temperature, which agrees with the results of magnetization measurements (T{sub C} = 84 K).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Structure of Gd{sub 0.95}Bi{sub 0.05}Fe{sub 3}(BO{sub 3}){sub 4} single crystals at 293 and 90 K

The structure of GdFe{sub 3}(BO{sub 3}){sub 4} single crystals has been studied by X-ray diffraction at 293 and 90 K. The crystals are grown from a flux in the Bi{sub 2}Mo{sub 3}O{sub 12}–B{sub 2}O{sub 3}–Li{sub 2}MoO{sub 4}–Gd{sub 2}O{sub 3}–Fe{sub 2}O{sub 3} system. The results of chemical analysis and structural study show that these crystals contain bismuth as an impurity. It is found that bismuth atoms are located at gadolinium sites in the structure. A decrease in the temperature is accompanied by a lowering of the symmetry from sp. gr. R32 (at 293 K) to sp. gr. P3{sub 1}21 (at 90 K). The presence of two types of iron chains with different geometries at 90 K promotes a change in the magnetic properties of these crystals with a decrease in the temperature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Coupling between phonon and crystal-field excitations in multiferroic PrFe 3 ( BO 3 ) 4

Far-infrared reflection and ellipsometry measurements on multiferroic PrFe 3 ( BO 3 ) 4 and SmFe 3 ( BO 3 ) 4 single crystals were used to investigate the interaction between lattice phonons and electronic excitations associated with 4 f crystal-field transitions. A temperature-dependent interference between two types of excitations was observed in PrFe 3 ( BO 3 ) 4 in which the frequency of 4 f crystal-field electronic excitation of Pr 3 + falls into the TO-LO frequency interval of the optical phonon mode near 50 cm - 1 (1.5 THz). Experimental data were explained on the basis of a theoretical model of coupled electron-phonon modes. The fitting procedure revealed the value 14.8 cm - 1 for the electron-phonon coupling constant. This rather large value points to an essential role played by the electron-phonon interaction in the physics of multiferroics.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

Crystal structure and magnetization of a Co{sub 3}B{sub 2}O{sub 6} single crystal

The crystal structure and magnetic properties of Co{sub 3}B{sub 2}O{sub 6} single crystals are studied. Orthorhombic symmetry with space group Pnnm is detected at room temperature. The measurements of static magnetization and dynamic magnetic susceptibility reveal two magnetic anomalies at T{sub 1} = 33 K and T{sub 2} = 10 K and an easy-axis magnetic anisotropy. The effective magnetic moment indicates a high-spin state of the Co{sup 2+} ion. A spin-flop transition is found at low temperatures and H{sub sf} = 23 kOe. EXAFS spectra of the K-edge absorption of Co are recorded at various temperatures, the temperature-induced changes in the parameters of the local environment of cobalt are analyzed, and the effective Co-Co and Co-O distances are determined. The magnetic interactions in the crystal are analyzed in terms of an indirect coupling model.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗