The atomic diffusion in the FeAl intermetallic compound with B2 ordered structure were studied by the kinetic Monte Carlo method. We use the pair interactions up to second neighbors with periodic boundary conditions to avoid surface effects. Diffusion constants was determined as a function of temperature, covering both ordered and disordered phases. In addition, we calculate the autocorrelation function which shows first, highly correlated jumps of the vacancy in the lattice at low temperatures and second, the atoms that jump to positions of its own sublattice at moderate temperatures.

An alternative method to determine the critical cooling rate of materials has been developed by explaining the size and cooling rate dependences of physical properties of metallic nanoparticles through the scaling theory. This method has been applied to silver and copper nanoparticles which have been obtained by molecular dynamics simulations. The results reveal that our values for critical rate are close for each studied physical quantity. Thus, by taking the average among them, we obtain 6.2(8) × 1012 K/s for silver and 8.9(5) × 1012 K/s for copper. We have also found the threshold size of nanoparticle behavior is independent of the cooling rate.

In this work, we made an analysis of the learning and teaching circumstances of the Physics School and in this context, we analyze an experiment that familiarizes the student with basic nuclear instrumentation which includes techniques and measurements methods of gamma rays spectrometry using radioactive sources of 22Na, 60Co, 137Cs and a NaI(Tl) scintillation detector. This experiment includes, also, the development of a multichannel analyzer prototype.

In the present work we determine the threshold of the nanoparticle behavior of copper nanoparticles by studying their structural and electronic properties. The studied nanoparticles contain from 13 to 8217 atoms and were obtained by molecular dynamics simulations using the Johnson potential for copper based on the embedded atom method. The results indicate that for small copper nanoparticles (o1000 atoms, 2.8 nm) the surface plays an important role in their physical properties. Whereas, for large nanoparticles (42000 atoms, 3.5 nm), with spherical-like external shape and large percentage of fcc-like local structure, this effect is negligible and their electronic character are similar to such expected in solid copper. Finally, it has also been shown that copper nanoparticles change their electronic character, from metallic to insulating, after increasing the strength of the chemical disor...

We thank DGAPA, UNAM project IN101019, and CONACYT grant A1-S-9070 of the Call of Proposals for Basic Scientific Research 2017–2018 for partial financial support. G.C.S. thanks Cienciactiva for financial support through the Doctoral Scholarship Program in Peruvian Universities (contract number 218-2014-FONDECYT). J.G.S thanks Aldo Rodriguez Guerrero for technical support. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, project LANCAD-UNAM-DGTIC-051.

L. M. S. gratefully acknowledges the International Max Planck Research School Dynamical processes in atoms, molecules and solids and the Deutscher Akademischer Austauschdienst (DAAD) for the financial support. G. C. S. and C. V. L. are grateful to the National Council of Science and Technology (CONCYTEC) from Peru for the financial support through the Doctoral Program for Peruvian Universities (No. 218-2014-FONDECYT) and the Peruvian Excellence Center Program, respectively. This work has also been partly supported by the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden”. We acknowledge the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for computational resources. Open Access funding provided by the Max Planck Society.