Crystal structure and magnetic properties of solid solutions Bi0,88 Sm0,12Fe1–xTixO3

Transparent Li2O-Al2O3-SiO2 low-expansion glass-ceramics have an undesirable brown color owing to Fe ions as a contaminant, whereas the mother glass normally has a clear appearance. Elucidation of the coloration mechanism during crystallization is important for industry to develop highly transparent materials. In this study, the mother glass contained SiO2, Al2O3, and Li2O as its principal constituents and TiO2 and ZrO2 as nucleation agents. The amount of contaminant Fe ions in the form of Fe2O3 was 0.03 wt%. It was confirmed that the coloration was appeared by the coexistence of Fe and Ti ions in the glass matrix based on the experimental results using Ti-containing and Ti-free glasses with a composition identical to that of the glass matrix. The coordination and oxidation state of the Fe ions were not changed by the coexistence of Ti ion according to the results of XANES measurement. The coloration is considered to be due to the formation of Fe-O-Ti by the concentration of Fe and Ti ions in the glass matrix phase during the crystallization process.

In the present work, we have synthesized rare-earth ion modified Bi4−xRExTi2Fe0.7Co0.3O12−δ (RE = Dy, Sm, La) multiferroic compounds by the conventional solid-state route. Analysis of X-ray diffraction by Rietveld refinement confirmed the formation of a polycrystalline orthorhombic phase. The morphological features revealed a non-uniform, randomly oriented, plate-like grain structure. The peaks evident in the Raman spectra closely corresponded to those of orthorhombic Aurivillius phases. Dielectric studies and impedance measurements were carried out. Asymmetric complex impedance spectra suggested the relaxation of charge carriers belonging to the non-Debye type and controlled by a thermally activated process. Temperature-dependent AC conductivity data showed a change of slope in the vicinity of the phase transition temperature of both magnetic and electrical coupling natures. Based on the universal law and its exponent nature, one can suppose that the conduction process is governed by a small polaron hopping mechanism but significant distortion of TiO6 octahedral. The doping of the A-sites with rare-earth element ions and changes in the concentrations of Fe and Co ions located on the B-sites manifested themselves in saturated magnetic hysteresis loops, indicating competitive interactions between ferroelectric and canted antiferromagnetic spins. The magnetic order in the samples is attributed to pair-wise interactions between adjacent Fe3+–O–Fe3+, Co2+/3+–O–Co3+/2+, and Co2+/3+–O–Fe3+ ions or Dzyaloshinskii–Moriya interactions among magnetic ions in the adjacent sub-lattices. As a result, enhanced magnetoelectric coefficients of 42.4 mV/cm-Oe, 30.3 mV/cm-Oe, and 21.6 mV/cm-Oe for Bi4−xDyxTi2Fe0.7Co0.3O12−δ (DBTFC), Bi4−xLaxTi2Fe0.7Co0.3O12−δ (LBTFC), and Bi4−xSmxTi2Fe0.7Co0.3O12−δ (SBTFC), respectively, have been obtained at lower magnetic fields (<3 kOe). The strong coupling of the Aurivillius compounds observed in this study is beneficial to future multiferroic applications.

The stoichiometric La-Ti doped strontium-barium niobate ceramic system was obtained for different concentrations of Titanium ions (Ti=1,3,5,10,30,50 %), where the Nb5− was substituted by Ti4+ according to the following expression Sr0.255 La0.03Bao0.7Nb2−yTiyO6−y/2 (LSBN-BST). The oxygen vacancies thus created which, together with the vacancies in the A sites of the tetragonal tungsten-bronze (TTB) material structure, have an important influence on their texture and dielectric properties, due to the crucial role of the occupancy of the crystallographic sites. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and thermoelectric analyses are reported. We report the first results for thin films of LSBNT- 7 % obtained by the PLD technique. The diffraction pattern reveals the presence of the LSBNT structure without annealing.

The equilibrium between titanium ions (Ti2+, Ti3+) and metallic titanium (Ti) in NaCl-KCl equimolar molten salt was investigated using TiCl3 and Ti. Equilibrium experiments were carried out in metal container of titanium or stainless-steel at 740°C. The concentrations of titanium ions were determined by chemical methods consisting of continuous three steps. Ti2+ and Ti were quantitated by H2 evolution method. Ti3+ was quantitated with titration by Fe3+. As the result, the concentration of Ti2+ was higher than that of Ti3+. The concentration quotient, Kc=(xTi3+)2⁄(xTi2+)3, depends on the concentration of Ti2+. The value of Kc at 740°C is recommended to be 5.9 at xTi2+=0.02 and 2.6 at xTi2+=0.07 respectively.

To investigate the effects of titanium (Ti) ions on the cell viability, the cell differentiation and the gene expressions related to bone resorption including Receptor Activator of NF-kappaB Ligand (RANKL) and Osteoprotegerin (OPG) in the tissues around dental implants, the osteoblast-, osteoclast-, and gingival epithelial-like cells were exposed to Ti ions. An MTS assay was carried out to evaluate the viabilities of osteoblast-like MC3T3-E1, osteoclast-like RAW264.7 and epithelial cell-like GE-1 cells. The gene expressions in these cells were analyzed by the use of RT-PCR and real-time quantitative RT-PCR. Ti ions in the concentration range 1-9 ppm had little effect on the viabilities of MC3T3-E1, RAW264.7 and GE-1, whereas 20 ppm Ti ions significantly decreased the viabilities of all cells. Analyses of RT-PCR and real-time quantitative RT-PCR data revealed that Ti ions at 9 ppm remarkably inhibited the expressions of Runx2, Osterix and type I collagen in MC3T3-E1. In RAW264.7, Ti ions showed no effects on the levels of mRNAs for TRAP and cathepsin K enhanced by RANKL. Ti ions at the range of 1-9 ppm showed no effects on the levels of mRNAs for RANKL and OPG in GE-1, while Ti ions at 9 ppm enhanced the expression of these genes in MC3T3-E1. These results, taken together, suggested that Ti ions show the biological effects, both on the viabilities of osteoblast and osteoclast and on the differentiation of either the osteoblastic or osteoclastic cells, which may influence the prognosis of dental implants.

Triethanolamine–cyclohexanone supported liquid membranes study for extraction and removal of nickel ions from nickel plating wastes

The release of ions is the initial stage of the corrosion process in an orthodontic wire. Continuous release of ions can reduce the effectiveness and performance of the orthodontic wire. Continuous release of ions in CuNiTi orthodontic wire can change the properties of the wire and trigger hypersensitivity reactions, also in stainless steel orthodontic wire which experiences continuous release of ions can reduce its stiffness. The tannin in avocado seeds is useful as a corrosion inhibitor it can inhibit the release of ions because they are able to bind with metal ions and form a passive layer also able to bind with Fe ions in stainless steel orthodontic wires to form a passive surface layer which is able to inhibit the release of ions when the corrosion process occurs. The aim of this research is to determine the effect of avocado seed extract as a corrosion inhibitor on the release of metal ions from CuNiTi and stainless steel orthodontic wires. Rectangular CuNiTi and stainless steel orthodontic wires measuring 0.017 x 0.025 inches were taken in 3 groups (1 control group soaked in artificial saliva and 2 treatment groups soaked in avocado seed extract). The samples were soaked in avocado seed extract with a concentration of 1.5 g/L and 2 g/L for 7 days. To see the release of ions, an X-Ray Fluorescence test is carried out. In CuNiTi orthodontic wire from the one way ANOVA test showed that there was a significant difference between the control group and all treatment groups on Cu, Ni and Ti ions. The Post Hoc LSD test showed that there were significant differences between the control group, treatment group 1 and treatment group 2 in Cu, Ni and Ti ions with a p value. In stainless steel orthodontic wire, the one way ANOVA test showed that there was a significant difference between the control group and all treatment groups in Fe and Ni ions but not significant in Cr ions in the ion release test with a p value <0.05. The Post Hoc LSD test showed that there were significant differences between the control group, treatment group 1 and treatment group 2 in Fe and Ni ions with a p value <0.05. Providing avocado seed extract with tannin content at concentrations of 1.5 g/L and 2 g/L can inhibit the rate of ion release in CuNiTi and stainless steel orthodontic wires due to the corrosion process.

The effects of temperature, Ti(III) ion concentration, and current density on the electrodeposition of Ti films were investigated in the eutectic LiF–LiCl melt at 823–973 K. The Ti(III) ions were prepared by adding Li2TiF6 and Ti metal to the melt. The diffusion coefficients of Ti(III) were 1.4, 1.8, 2.3, and 3.2 × 10−5 m2 s−1, at 823, 873, 923, and 973 K, respectively. Galvanostatic electrolysis was conducted at 823–973 K. The surface roughness (S a) of the Ti films decreases with decreasing temperature. Thus, the electrodeposition of Ti films was conducted at the lowest temperature of 823 K with various Li3TiF6 concentrations (0.55–7.1 mol%) and cathodic current densities (50–1200 mA cm−2). The S a was lower at higher Ti(III) ion concentrations and lower current densities. The smoothest Ti films with a S a of 1.23 μm and a thickness of 10 μm were obtained at a cathodic current density of 50 mA cm−2 and Li3TiF6 concentration of 7.1 mol%.

Spin-related phenomena, such as the giant magnetoresistance and the spin-transfer torque, have led to a new era of nano-spintronics in last two decades. The discovery of these physical phenomena has contributed to a substantial increase in the data storage capacity of computers. Another revolutionary phenomenon, the interfacial Dzyaloshinskii-Moriya interaction (DMI), was recently discovered in ultra-thin ferromagnet/heavy-metal bilayers. The DMI stabilizes nanometre-sized chiral spin textures such as Neel domain walls and hedgehog skyrmions. These chiral objects find the potential for applications in ultra-high density, low-energy, and high-speed memory devices because they are stable due to topological protection and easy to move with high efficiency. As both stability and current-driven speed of chiral spin textures are proportional to the DMI strength [A. Thiaville et al., Europhys Lett. 100, 57002 (2012); A. Fert, V. Cros, and J. Sampiao, Nat. Nanotechnol. 8, 152 (2013)], tremendous efforts are being devoted to finding high-DMI materials. In this respect, understanding the microscopic origin of DMI is of critical importance. Here we discuss the microscopic origin of the interfacial DMI with experimental and theoretical studies as follows: First, we show the temperature dependence of the DMI for a Pt/Co/MgO trilayer; the DMI increases with decreasing temperature in a range from 300 to 100 K. To discuss this temperature dependence of the DMI, that of the spin and orbital magnetic moments of Co and Pt is studied by X-ray magnetic circular dichroism (XMCD) spectroscopy. We find that spin moment values of Co and Pt show temperature dependences due to change in Heisenberg exchange. Furthermore, the intra-atomic magnetic dipole moment, which is due to the asymmetric spin-density distribution, shows strong temperature dependence, suggesting a sizable modification of the charge distribution between the in-plane and the out-of-plane d-orbitals under temperature variation. We also find that the out-of-plane orbital moment shows large temperature dependence while in-plane orbital moment does not, revealing a close connection between the anisotropy of orbital moment and the DMI. The ab-initio and the tight-binding model calculations suggest that the ISB-dependent electron hopping, which gives rise to the asymmetric charge distribution at the interface of the FM/HM, is a possible microscopic origin of the correlation between the orbital anisotropy and the DMI.

The Dzyaloshinskii-Moriya interaction (DMI) in magnetic materials plays an important role in spintronics, giving rise to chiral spin textures such as the nucleation and propagation of domain walls and skyrmions. The necessary ingredient for the emergence of the DMI is the lack of inversion symmetry combined with elements with strong spin-orbit coupling. We report on a first-principles investigation of generalized DMIs in bulk centrosymmetric crystals with noncentrosymmetric local sublattices, where we consider a prototype family of $\mathcal{PT}$-symmetric antiferromagnets, including, ${\mathrm{Mn}}_{2}\mathrm{Au}$, ${\mathrm{MnPd}}_{2}$ and MnCuAs in the tetragonal and orthorhombic phases. We employ a Green's function approach to calculate the interatomic relativistic exchange coupling which can, in turn, determine the sublattice elements of the generalized fifth-order DMI tensor ${D}_{\ensuremath{\alpha}\ensuremath{\beta},\ensuremath{\gamma}}^{s{s}^{\ensuremath{'}}}$. We demonstrate that the breaking of the local mirror symmetry and the resulting local Rashba-type spin-momentum locking yield local DMIs with opposite signs on the two antiparallel sublattices. We present numerical results and provide analytical expressions for the magnon dispersion in the presence of the sublattice DMI and show that the intra- (inter-) sublattice DMIs result in identical (opposite) contributions to the nonreciprocal components of the two low-frequency antiferromagnetic magnon modes.

Features of the magnetization in ceramics Bi0.86Sm0.14Fe1-xMnxO3 in the rhombohedral - orthorhombic morphotropic phase boundary

Recovery and concentration of metals from red mud by Donnan dialysis

Objective To explore the distribution of serum Mg, Al, Ca, Fe, Zn and Cu ions in Tibetan population in drinking tea type fluorosis areas, and to provide a clue for pathogenesis of drinking tea type fluorosis. Methods Tibetans from six villages in Qinghai Province (Maqin County and Dari County), who were over 16 years old, born and grew up in those villages, were included. All of the participants were received epidemic questionnaire survey, tea water samples were collected and the fluoride concentration was tested based on the standard of Brick Tea Fluoride Content (GB 19965-2005). Meanwhile, the daily amount of brick tea consumption was surveyed to calculate the daily intake of tea fluoride. Blood samples were collected and the concentration of serum Mg, Al, Ca, Fe, Zn and Cu ions was tested by the method of inductively coupled plasma mass spectrometry (ICP-MS). All of the participants were diagnosed by X-ray, the parts we scheduled were forearm, shank and pelvic, then the skeletal fluorosis was diagnosed based on the Diagnostic Criteria for Endemic Fluorosis (WS/T 192-2008). Results A total of 170 people were surveyed, 74 people were skeletal fluorosis, and 96 people were non-skeletal fluorosis. The median (quartiles) of daily intake of tea fluoride was 7.35 (3.00, 12.30) mg. The concentration of serum Mg ion was 22.02 (17.30, 23.67) mg/L, Al ion was 0.22 (0.14, 0.38) mg/L, Ca ion was 100.03 (88.56, 112.73) mg/L, Fe ion was 1.66 (1.26, 2.36) mg/L, Zn ion was 0.80 (0.63, 0.95) mg/L and Cu ion was 1.28 (0.99, 1.48) mg/L. The concentration of serum Fe ion was higher in male [2.13 (1.37, 3.09) mg/L] than that of female [1.56 (1.18, 2.02) mg/L, Z= 3.28, P 0.05). Conclusions In the Tibetans who lived in the drinking tea type fluorosis areas, the concentration of serum Mg, Al, Ca, Fe, Zn and Cu ions is similar between skeletal fluorosis and non-skeletal fluorosis, which is also similar between higher daily intake of tea fluoride and lower daily intake of tea fluoride. However, it is different between older people and younger people. Key words: Fluorine; Minority groups; Ions

Salinity, temperature and pressure effect on hydrogen wettability of carbonate rocks

Recent demonstration of the interfacial Dzyaloshinskii-Moriya interaction (DMI) between a heavy metal and a magnetic insulator provides the possibility to manipulate chiral spin textures in the magnetic insulator for the extremely low power consumption devices. However, the origin and strength of the interfacial DMI remain in dispute in this system. We used the electrical transport measurements to determine the DMI strength to be ∼0.040 pJ/m at room temperature in Pt/Tm3Fe5O12 (TmIG) bilayers. The TmIG saturation magnetization and DMI strength exhibit different temperature dependences, which is attributed to the DMI being mainly contributed by Fe ions instead of Tm ions. With a Cu layer inserted between Pt and TmIG, the DMI strength is reduced to ∼0.012 pJ/m and the topological Hall effect vanishes, strongly suggesting that the Pt/TmIG interface has important contribution to the DMI.