109 research outputs found
Evidence for differentiation in the iron-helicoidal-chain in GdFe(BO)
We report on a single-crystal X-ray structure study of
at room temperature and at T=90 K. At room temperature
crystallizes in a trigonal space group R32 (No. 155), the same as found for
other members of iron-borate family . At 90 K the
structure of has transformed to the space group
(No. 152). The low-temperature structure determination gives new
insight into the weakly first-order structural phase transition at 156 K and
into the related Raman phonon anomalies. The discovery of two inequivalent iron
chains in the low temperature structure provide new point of view on the
low-temperature magnetic properties.Comment: Subm. to Acta Cryst.
The influence of the industrial complex on the atmospheric air in the Sverdlovsk region
The work is dedicated to studying the level dynamics of polluting substances emissions into the atmosphere of Yekaterinburg city and the Sverdlovsk region in the period of 2012-2016. In the process of our work we found out an insignificant reduction of main indicators values such as SI, HR, and IPA to estimate the atmospheric air quality. Nevertheless, the level of the air pollution in Yekaterinburg city remained high in the stated period. We also suggested some methods to reduce enterprises emissions in the article, which will lead to improving the air quality. In the result of our work it was established that the main pollutants are suspended particles, nitrogen dioxides, phenol, and benzene. Moreover, the connection between the atmospheric air pollution degree and the Sverdlovsk region population's health was determined. © 2018 Institute of Physics Publishing. All rights reserved
Magnetization and specific heat of TbFe3(BO3)4: Experiment and crystal field calculations
We have studied the thermodynamic properties of single-crystalline
TbFe3(BO3)4. Magnetization measurements have been carried out as a function of
magnetic field (up to 50 T) and temperature up to 350K with the magnetic field
both parallel and perpendicular to the trigonal c-axis of the crystal. The
specific heat has been measured in the temperature range 2-300K with a magnetic
field up to 9 T applied parallel to the c-axis. The data indicate a structural
phase transition at 192 K and antiferromagnetic spin ordering at 40 K. A
Schottky anomaly is present in the specific heat data around 20 K, arising due
to two low-lying energy levels of the Tb3+ ions being split by f-d coupling.
Below TN magnetic fields parallel to the c-axis drive a spin-flop phase
transition, which is associated with a large magnetization jump. The highly
anisotropic character of the magnetic susceptibility is ascribed mainly to the
Ising-like behavior of the Tb3+ ions in the trigonal crystal field. We describe
our results in the framework of an unified approach which is based on
mean-field approximation and crystal-field calculations.Comment: 10 pages, 10 figures, 20 references, accepted by Phys. Rev.
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