Impact of Cr Doping on the Structural, Optical, and Magnetic Properties of Sol-Gel-Synthesized Bi0.80Ba0.10Pr0.10FeO3 Nanopowders.

The sol-gel route was used to synthesize a series of compounds of the system Bi0.8Ba0.10Pr0.10Fe1-x Cr x O3 within the 0 ≤ x ≤ 0.15 compositional range. To explore the impact of Cr3+ ion substitution on the structural, dielectric, optical, and magnetic properties, we introduced varying concentrations of Cr3+ while maintaining a fixed 10% atomic concentration of each Ba2+ and Pr2+ in BiFeO3. X-ray diffraction analysis revealed a structural phase transition from rhombohedral (R3c) for an undoped (i.e., without Cr) sample to two coexisting phases, i.e., a mix of rhombohedral and orthorhombic (Pbnm) phases for the Cr-doped samples. Cr3+ doping significantly changes the band gap energy from 1.84 eV (x = 0.0) to 1.93 eV (x = 0.15), which makes this material suitable for photovoltaic applications. Furthermore, each sample exhibited ferromagnetic behavior due to the disruption of the spiral spin structures and adjustments in superexchange interactions, attributed to modifications in the Fe-O and Fe-O-Fe bond lengths. A reduction in magnetization is observed at higher Cr concentrations that can be ascribed to the dilution of magnetic moments due to the increase of the orthorhombic phase percentage and the introduction of nonmagnetic Cr3+ ions. Our results show that Cr doping in the Bi0.8Ba0.10Pr0.10FeO3 system induces enhanced multiferroic properties at room temperature.

Predicting the stability and electronic structure of alkali metal aurides.

Density functional theory calculations of phonon modes predict that some compounds of the alkali metal aurides family, general formulaA2MAu6(A= K, Rb or Cs;M= Ti, Zr, Hf, Sn or Pb), have stable three-dimensional phase with a double perovskite-type structure and cubicFm3¯mspace group (K2PtCl6-type). Bader's charge analysis shows that most electron density is located within the six atoms at the octahedra vertices like double perovskite halides. However, the short spacing between Au anions enables d-orbital interactions between them. Compounds of this family, with group 4 metals only, carry conduction states around the Γ point (k= 0). On the other hand, compounds with group 14 metals possess more conduction states around all the Brillouin zone and have electron pockets in their band structures. These compounds provide further insights into the unusual anionic behavior of gold and present other alternatives for the construction of divergent nanodevices.

Individualidad genética y la Declaración Universal sobre el Genoma Humano y los Derechos Humanos / No disponible

El artículo explora la relación epistémica y ontológica entre Ciencia y Derecho a partir del concepto de individuo en la Declaración Universal sobre el Genoma Humano y los Derechos Humanos. Se argumenta en favor de una mejor comprensión de dicha relación para prever posibles consecuencias éticas y sociales de la Ley derivadas de conceptos con un fuerte significado científico (AU)

In this article we explore the epistemic and ontological relationship between Science and Law through the concept of individual in the Universal Declaration of the Human Genome and Human Rights. We argue for a better understanding of this relationship in order to foresee ethical and social consequences derived from Law adopting concepts with a strong scientific meaning (AU)

[Genetic individuality and the universal declaration on the human genome and human rights]. / Individualidad genética y la declara- ción universal sobre el genoma hu- mano y los derechos humanos.

In this article we explore the epistemic and ontological relationship between science and law through the concept of individual in the Universal Declaration of the Human Genome and Human Rights. We argue for a better understanding of this relationship in order to foresee ethical and social consequences derived from Law adopting concepts with a strong scientific meaning.