Physics

Research from M. Behar and co-authors reveals new findings on physics

  2010 FEB 9 - (VerticalNews.com) -- "The electronic stopping power, S, of HfO2 films for proton and alpha particle beams has been measured and calculated. The experimental data have been obtained by the Rutherford backscattering technique and cover the range of 120-900 and 120-3000 keV for proton and alpha particle beams, respectively," researchers in Porto Alegre, Brazil report.

  "Theoretical calculations of the energy loss for the same projectiles have been done by means of the dielectric formalism using the Mermin energy loss function-generalized oscillator strength (MELF-GOS) model for a proper description of the HfO2 target on the whole momentum-energy excitation spectrum. At low projectile energies, a nonlinear theory based on the extended Friedel sum rule has been employed. The calculations and experimental measurements show good agreement for protons and a quite good one for alpha particles. In particular, the experimental maximums of both stopping curves (around 120 and 800 keV, respectively) are well reproduced. On the basis of this good agreement, we have also calculated the inelastic mean-free path (IMFP) and the stopping power for electrons in HfO2 films," wrote M. Behar and colleagues.

  The researchers concluded: "Our results predict a minimum value of the IMFP and a maximum value of the S for electrons with energies around 120 and 190 eV, respectively."

  Behar and colleagues published their study in Physical Review a (Energy loss of proton, alpha particle, and electron beams in hafnium dioxide films. Physical Review a, 2009;80(6):2901).

  For additional information, contact M. Behar, University of Fed Rio Grande do Sul, Inst Fis, Av Bento Goncalves 9500, BR-91501970 Porto Alegre, RS, Brazil.

  Publisher contact information for the journal Physical Review a is: American Physical Society, One Physics Ellipse, College Pk, MD 20740-3844, USA.

  Keywords: City:Porto Alegre, Country:Brazil, Alpha Particle, Physics.

  This article was prepared by VerticalNews Physics editors from staff and other reports. Copyright 2010, VerticalNews Physics via VerticalNews.com.