Number Of Ternary Compounds Research Articles

Isothermal sections of the Nd–M–Sb systems at 870 K (M=Cr, Fe, Co, Zn)

Abstract Equilibrium phase diagrams for the ternary systems Nd–{Cr,Fe,Co,Zn}–Sb at 870 K have been determined and analyzed for the first time. The phase field distributions in these systems at 870 K are characterized by the presence of only a small number of ternary compounds: For M=Cr, Fe, Co and Zn we observed one, two, and three ternary antimonides, respectively.

Lattice dynamics and chemical binding in semiconducting compounds II-IV-V2

A review is given of experimental studies of infrared absorption, reflection, and Raman scattering of light on single crystals of I!--IV--V2 compounds. A rigid ion model is discussed as applied to the calculation of phonon spectra of ternary compounds with the chalcopyritetype lattice. In the simplest version of the model, short-range forces in the nearestneighbor approximation are given with the help of three parameters; Coulomb forces in the model of unpolarized ions are determined by two parameters. The dependence of phonon spectra on the ratio of cation masses is analyzed: a similarity between phonon spectra of ternary compound with similar cation masses and analogous binary compounds, placed in the Brillouin zone of chalcopyrite, as well as significant qualitative differences between spectra of binary and ternary semiconductors for a significant difference in cation masses is indicated. The calculated frequency density function, taken with a double scale g(2~), describes qualitatively the full symmetry component of the Raman scattering spectrum of second order. From the analysis of calculated elastic constants is has been established that in a number of ternary compounds a tendency is observed for decrease of elastic constants as the average atomic number is increased. Anisotropy of propagation of elastic waves in ternary compounds is analyzed. From the comparison of theoretical and experimental temperature dependences of the specific heat it has been shown that the Debye model does not describe experiment as well as the model which takes into account the real structure of the phonon spectrum.

The interaction of transition and rare earth metals with boron

From our measurements on the R-M-B systems 47 phase equilibria diagrams were constructed and 142 new ternary borides were found. An analysis of the data we obtained showed that the number of ternary compounds in the R-M-B systems increases as the difference between the electronegativities of the transition and rare earth metals increases. The ternary borides of the R-M-B systems are characterized by the formation of new types of structure and by the formation of two homologous series, one based on the CaCu 5-type and the CeCo 3B 2-type structures and the other on the MgZn 2-type and the CeCo 3B 2-type structures.

Neutron scattering observations on the magnetic phases of rare-earth ternary superconductors

A number of ternary compounds become superconducting even though they contain a chemically ordered sublattice of magnetic rare-earth ions. Studies of the physical properties of these materials have revealed anomalies below Tc which have been attributed to magnetic ordering transitions. Using neutron spectrometers at the Brookhaven National Laboratory, a group of us has demonstrated that simple magnetic structures with long-range order do occur, and we have solved some of the magnetic structures of these superconductors. Specifically, we have found that in DyMo6S8 and TbMo6S8 an antiferromagnetic structure coexists with superconductivity. In two other compounds, ErRh4B4 and HoMo6S8 we have found that the development of ferromagnetism is responsible for the quenching of superconductivity. A study of the critical magnetic neutron scattering near the superconducting → ferromagnetic transitions shows the presence of fluctuations into a state with an oscillatory magnetization of wave length λ=100 Å.