Comment on "dependence of volume changes during solid solution formation and of volume size factor on solute volume, group number and crystalline structure by O. Coreño-Alonso, J. Coreño-Alonso, Intermetallics 2012; 22:142"

We comment on the derivation as well as the applicability of the equation used for the bulk modulus of substitutional alloys in terms of the bulk moduli of the pure end members. © 2012 Elsevier Ltd. All rights reserved

Comment on "liH as a Li+ and H- ion provider by Khang Hoang, Chris G. Van de Walle, Solid State Ionics 253 (2013) 53"

A first-principle study of the formation and migration of native defects in LiH, a material of interest in hydrogen storage and lithium-ion batteries, has just been published by Hoang and Van de Walle [Solid State Ionics 253 (2013) 53-56]. Their results are found here to be of key-importance to deduce useful results for the pressure dependence of the ionic conductivity of LiH. © 2014 Elsevier Ltd. All rights reserved

Comments on the elastic properties in solid solutions of silver halides

Recently first principles microscopic calculations, using the generalized gradient approximation, appeared for the solid mixed system AgCl xBr 1-x at various compositions. Here, we suggest a model that can estimate the compressibility of the mixed crystals in terms of the compressibilities of the end members alone. This model makes use of a single parameter, i.e. the compressibility of a defect volume, when considering the volume variation produced by the addition of a "foreign molecule" to a host crystal as a defect volume. © 2012 World Scientific Publishing Company

On the increase of the "non-uniform" scaling of the magnetic field variations before the Mw 9.0 earthquake in Japan in 2011

By applying Detrended Fluctuation Analysis (DFA) to the time series of the geomagnetic data recorded at three measuring stations in Japan, Rong et al. in 2012 recently reported that anomalous magnetic field variations were identified well before the occurrence of the disastrous Tohoku Mw9.0 earthquake that occurred on 11 March 2011 in Japan exhibiting increased "non-uniform" scaling behavior. Here, we provide an explanation for the appearance of this increase of "non-uniform" scaling on the following grounds: These magnetic field variations are the ones that accompany the electric field variations termed Seismic Electric Signals (SES) activity which have been repeatedly reported that precede major earthquakes. DFA as well as multifractal DFA reveal that the latter electric field variations exhibit scaling behavior as shown by analyzing SES activities observed before major earthquakes in Greece. Hence, when these variations are superimposed on a background of pseudosinusoidal trend, their long range correlation properties - quantified by DFA - are affected resulting in an increase of the "non-uniform" scaling behavior. The same is expected to hold for the former magnetic field variations. This explanation is strengthened by recent findings showing that the fluctuations of the order parameter of seismicity exhibited an unprecedented minimum almost two months before the Tohoku earthquake occurrence which is characteristic for an almost simultaneous emission of Seismic Electric Signals activity. © 2014 AIP Publishing LLC

Comments on the electrical conductivity in solid solutions of the silver halide-cadmium halide systems

Very recent measurements of the electrical conductivity of solid systems AgX-CdX2 (where X ≡ Cl, Br) that form large areas of solid solutions, have shown that maximum conductivity occurs for a concentration around 20 mol% of the cadmium halide. Here, we suggest a quantitative explanation of this phenomenon based on a model that was recently suggested (J. Appl. Phys. 103, 083552, (2008)) for estimating the compressibility of multiphased mixed crystals. In addition, explicit conditions are obtained which predict when such a conductivity maximum is expected to occur. © 2010 Elsevier B.V. All rights reserved

On a universal relation for defect data in solids

We show that the defect data parameters related to various defect processes, e.g., formation, migration, dielectric relaxation parameters, obey a universal law. In particular, the defect entropies scale with the defect enthalpies irrespective of the process considered. A concrete example is given here for SrF2 by considering the dielectric relaxation parameters (R1 relaxation mechanism) for crystals doped with trivalent ions of Ce, Eu, and Gd, parameters for the anion-Frenkel formation as well as for the migration of anion vacancy and the anion interstitial motion. © 2010 Elsevier B.V. All rights reserved