The Solubility of Indium in Liquid Gallium Supercooled to 12 K

The method of perturbed angular correlation (PAC) was used to determine lattice locations of 111In impurity probe atoms present in extreme dilution in the intermetallic compound FeGa3. In slightly Ga-poor samples, probes were found to strongly prefer one of two inequivalent Ga-sites. In slightly Ga-rich samples at room temperature, 293 K, the PAC spectrum exhibited an unperturbed quadrupole interaction signal that is consistent with indium probes dissolved in small liquid pools of the excess Ga. A myriad of such pools are probably located along grain boundaries in the sample. Cooling from 293 K down to 12 K, the site fraction of indium in liquid decreased, being offset by the increase in a signal attributed to indium solutes in precipitates with other impurities at the sides of the Ga pools. However, these changes were completely reversible upon heating, and no crystallization of the liquid gallium pools was observed down to 12 K. This is attributed to the extraordinarily small volumes for the pools, which, while not measured directly, are orders of magnitude smaller than cubic microns. The measured temperature dependence of the site fraction of indium in the liquid was used to extend the metastable solubility curve for indium in liquid gallium down to a temperature of 150 K, much lower than the eutectic temperature of Ga-In at 288.5 K.

Computer Simulation Model for First-Order Phase Transition Fluctuation Stage

Ion irradiation of surfaces leads to blistering (vacancy-gaseous bubbles formation into crystal lattice) and/or nano-scale islands of thin cover formation. Stochastic model of first order phase transition at fluctuation stage is presented by superposition of Wiener processes of nuclei clustering and it’s Brownian motion. Solution of Ito-Stratonovich stochastic differential equations allows studying the evolution of distribution functions versus clusters sizes and relative lattice locations of nuclei.

Lattice Locations of 12B in CaB6

The nuclear quadrupole interaction of the short-lived -emitter 12B implanted into CaB6 crystal has been studied by means of modified β-NMR (β-NQR) technique. The electric field gradient at the implanted 12B was found to be = q-(1.34±0.05)x1021 V/m2 at room temperature. From this result it is concluded that the 12B probe nuclei are mainly implanted in the substitutional boron site and are applicable to systematic NMR studies of ferromagnetic La doped CaB6

Lattice Location of Deuterium in Plasma and Gas Charged Mg Doped GaN

We have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced by exposure to gas phase or ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Results of channeling measurements are compared with channeling simulations for hydrogen at lattice locations predicted by density functional theory.