Analysis of Crystal Structure and Dielectric of Zn2+ Ion Doped Nanoparticle Magnetite Based on Iron Sand Synthesized by Coprecipitation Method

Zn2+ ion doped Fe3O4 nanoparticles based on iron sand have been successfully synthesized by coprecipitation method at low temperature. The starting materials were iron sand, ZnCl2, HCl, and NH4OH. Characterizations were conducted by means of X-Ray Flourescence (XRF), X-Ray Diffraction (XRD) and digital capacitance meter AD5822. XRF identification confirms that the elemental composition of all samples is appropriate with the stoichiometry calculation. Phase formation identification by using High Score Plus and DDView+PDF2 software reveals that all samples crystallize in cubic spinel structure. Rietveld refinement analysis bymeans of Reitica yields the doping of Zn2+ ion on Fe3O4 increases the lattice parameter with crystal size in the order of nanometer. This is in line with theoretical predictions as a consequence of the influence of Zn2+ ionic radii that replace Fe2+. Furthermore, dielectricity analysis shows that the higher the amount of Zn2+ doped Fe3O4 nanoparticles the higher the dielectric constant. This mechanism is ionic polarization phenomenom as consequence of the decreasing in the crystal volume and the atomic distance that lead to increase the moment of dipole

Analysis Crystal Structure of Thin Films Bazr0.2ti0.8o3 Which Have Deposited by Sol Gel Method

Fabrication of BaZr0.2Ti0.8O3 thin film on Si substrate by sol gel method use spin coater has been done successfully. Bariumasetat, zirconiumisoproponol, titaniumisopropoksid were used as deposition components BZT thin film. Asetat acid and etylen glycol were used as solvent. There are three basic principles of thin film fabrication by sol gel method, i.e. chemical process (Solvent fabrication), thin film deposition use spin coater, and thermal process (annealing). The layers number variation has done to get layer which become target in this research. Speed and duration of spin coater rotation were set at 3000 rpm for 30 seconds, while annealing temperature and duration were set in 8000 °C for 3 hours. Characterization that we have done i.e. X-Ray Flurosence (XRF) test to observe the composition of thin film BZT and X-Ray Diffraction (XRD) test to observe crystal structure. The XRF characterization results show that deposition components of BZT thin film have deposited on Si substrate. The implication of more layers number which have formed is more components BZT thin film which have deposited. The XRD characterizations results show that crystality of BZT thin film because raise some peaks which have been cross check by ICDD database and conclude that the owner of some peaks is BZT. The conclusions have strength by smoothing results by General StuctureAnalysis System (GSAS) software. The implication ofmore layers number is more high intensity on certain oriented plane. Keywods: Sol gel, BZT, XRD, XRF, GSAS

Crystal structure analysis of intermetallic compounds

Study concerns crystal structures and lattice parameters for a number of new intermetallic compounds. Crystal structure data have been collected on equiatomic compounds, formed between an element of the Sc, Ti, V, or Cr group and an element of the Co or Ni group. The data, obtained by conventional methods, are presented in an easily usable tabular form

Predicting the Volumes of Crystals

New crystal structures are frequently derived by performing ionic substitutions on known crystal structures. These derived structures are then used in further experimental analysis, or as the initial guess for structural optimization in electronic structure calculations, both of which usually require a reasonable guess of the lattice parameters. In this work, we propose two lattice prediction schemes to improve the initial guess of a candidate crystal structure. The first scheme relies on a one-to-one mapping of species in the candidate crystal structure to a known crystal structure, while the second scheme relies on data-mined minimum atom pair distances to predict the crystal volume of the candidate crystal structure and does not require a reference structure. We demonstrate that the two schemes can effectively predict the volumes within mean absolute errors (MAE) as low as 3.8% and 8.2%. We also discuss the various factors that may impact the performance of the schemes. Implementations for both schemes are available in the open-source pymatgen software.Comment: 8 figures, 2 table

Raman Spectroscopic and SEM Analysis of Sodium-Zippeite

Raman at 298 and 77 K and infrared spectra of two samples of sodium-zippeite were studied and interpreted. U-O bond lengths in uranyl were calculated and compared with those inferred from the X-ray single crystal structure data of a synthetic sodium-zippeite analog. Hydrogen-bonding network in the studied samples is discussed. O-H…O bond lengths were calculated and compared with those predicted from the X-ray single crystal structure analysis

Theory of Exciton Recombination from the Magnetically Induced Wigner Crystal

We study the theory of itinerant-hole photoluminescence of two-dimensional electron systems in the regime of the magnetically induced Wigner crystal. We show that the exciton recombination transition develops structure related to the presence of the Wigner crystal. The form of this structure depends strongly on the separation $d$ between the photo-excited hole and the plane of the two-dimensional electron gas. When $d$ is small compared to the magnetic length, additional peaks appear in the spectrum due to the recombination of exciton states with wavevectors equal to the reciprocal lattice vectors of the crystal. For $d$ larger than the magnetic length, the exciton becomes strongly confined to an interstitial site of the lattice, and the structure in the spectrum reflects the short-range correlations of the Wigner crystal. We derive expressions for the energies and the radiative lifetimes of the states contributing to photoluminescence, and discuss how the results of our analysis compare with experimental observations.Comment: 10 pages, no figures, uses Revtex and multicol.st