Stochastic hyperfine interactions modeling library—Version 2

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract The stochastic hyperfine interactions modeling library (SHIML) provides a set of routines to assist in the development and application of stochastic models of hyperfine interactions. The library provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) find the eigenvalues and eigenvectors of the Blume matrix so that theoreti... Title of program: SHIML Catalogue Id: AEIF_v2_0 Nature of problem In condensed matter systems, hyperfine methods such as nuclear magnetic resonance (NMR), Mössbauer effect (ME), muon spin rotation (ΜSR), and perturbed angular correlation spectroscopy (PAC) measure electromagnetic fields due to electronic and magnetic structure within Angstroms of nuclear probes through the hyperfine interaction. When interactions fluctuate at rates comparable to the time scale of a hyperfine method, there is a loss in signal coherence, and spectra in the time domain are damped ... Versions of this program held in the CPC repository in Mendeley Data AEIF_v1_0; SHIML; 10.1016/j.cpc.2010.12.042 AEIF_v2_0; SHIML; 10.1016/j.cpc.2015.10.01

Stochastic hyperfine interactions modeling library

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract The stochastic hyperfine interactions modeling library (SHIML) provides a set of routines to assist in the development and application of stochastic models of hyperfine interactions. The library provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) find the eigenvalues and eigenvectors of the Blume matrix so that theoreti... Title of program: SHIML Catalogue Id: AEIF_v1_0 Nature of problem In condensed matter systems, hyperfine methods such as nuclear magnetic resonance (NMR), Mössbauer effect (ME), muon spin rotation (ΜSR), and perturbed angular correlation spectroscopy (PAC) measure electronic and magnetic structure within Angstroms of nuclear probes through the hyperfine interaction. When interactions fluctuate at rates comparable to the time scale of a hyperfine method, there is a loss in signal coherence, and spectra are damped. The degree of damping can be used to determine ... Versions of this program held in the CPC repository in Mendeley Data AEIF_v1_0; SHIML; 10.1016/j.cpc.2010.12.042 AEIF_v2_0; SHIML; 10.1016/j.cpc.2015.10.01

Predicted calcium titanate solution mechanisms in calcium aluminoferrite and related phases

Computer simulation, using an ionic, Born-like model, is used to investigate the accommodation of titanium impurities in Ca-Al-Fe-O phases. Specifically, calcium titanate solution in Al2O3, Fe2O3, CF, C2F, CA, C(2)A, C(3)A, and C(4)AF (where C denotes CaO) is considered. The simulations predict that titanium impurities are found preferentially in the ferrite phases. At sufficiently high concentrations, the solution involves the formation of clusters containing 3 to 6 ions that strongly resemble the structure of the calcium titanate phase. The calculations reveal that the compensation mechanism varies appreciably over the range of compounds considered. (C) 2000 Kluwer Academic Publishers

Solute-solute interactions in intermetallic compounds

Experiments were carried out on highly ordered GdAl 2 samples containing extremely dilute mole fractions of 111 In/Cd probe-atom solutes (about 10 −11 ), intrinsic antisite atoms Al Gd having mole fractions of order 0-10 −2 , and doped with Ag solutes at mole fractions of order 10 −2 . Three types of defect interactions were investigated. (1) Quadrupole interactions caused by Ag-solute atoms neighboring 111 In/Cd solute probe atoms were detected using the method of perturbed angular correlation of gamma rays (PAC). Three complexes of pairs of In-probes and Ag-solutes occupying neighboring positions on Gd- and Al-sublattices were identified by comparing site fractions in Gd-poor and Gd-rich GdAl 2 (Ag) samples and from the symmetry of the quadrupole interactions. Interaction enthalpies between solute-atom pairs were determined from temperature dependences of observed site fractions. Repulsive interactions were observed for close-neighbor complexes In Gd +Ag Gd and In Gd +Ag Al pairs, whereas a slightly attractive interaction was observed for In Al +Ag Al . Interaction enthalpies were all small, in the range ±0.15 eV. (2) Quadrupole interactions caused by intrinsic antisite atoms Al Gd neighboring In Gd probes were also detected and site fractions measured as a function of temperature, as in previous work on samples not doped with Ag-solutes [Temperature- and composition-driven changes in site occupation of solutes in Gd 1+3x Al 2−3x , Zacate and Collins (Phys. Rev. B69 , 174202 ( 1 ))]. However, the effective binding enthalpy between In Gd probe and Al Gd antisite was found to change sign from -0.12 eV (attractive interaction) in undoped samples to + 0.24 eV (repulsive) in Ag-doped samples. This may be attributed to an attractive interaction between Al Gd antisite atoms and Ag-dopants that competes with the attractive interaction between In Gd and Al Gd defects observed in undoped samples. Alternatively, it may be attributed to competing flows of Ag and Al atoms that, in effect, change the numbers of available si

H-PASSIVATION OF THE DOUBLE ACCEPTOR-CD IN GE

Pfeiffer W, BURCHARD A, DEICHER M, et al. H-PASSIVATION OF THE DOUBLE ACCEPTOR-CD IN GE. In: Solid State Communications. Solid State Communications. Vol 93. Elsevier; 1995

Cadmium-hydrogen shallow acceptor complexes in germanium

HSU L, HALLER EE, Pfeiffer W, et al. Cadmium-hydrogen shallow acceptor complexes in germanium. Solid State Communications. 1995;93(5):459-459

Diffusion in Intermetallic Compounds Studied Using Nuclear Quadrupole Relaxation

Abstract. The jump frequency of Cd tracer atoms was measured as a function of temperature in seven rare-earth tri-indide intermetallic compounds having the L12, or Cu3Au, structure. The frequency, proportional to the diffusivity, was detected by relaxation of nuclear quadrupole interaction at Cd nuclei caused by reorientation of the electric field gradient in each diffusive jump. Measurements were made using perturbed angular correlation of gamma rays, sensitive to jump frequencies in the range 1-1000 MHz. Results are as follows. (1) Jump frequencies measured in LaIn3 and CeIn3 were observed to be 10-100 times greater at the more In-rich boundary composition than the less In-rich boundary composition, even though the phases appear as line compounds in phase diagrams. (2) Arrhenius plots of the jump frequency were fitted to activation enthalpies that increase from 0.535 to 1.80 eV across the series of phases LaIn3, CeIn3, PrIn3, and NdIn3