@article{10902/520,
year = {2008},
month = {9},
url = {http://hdl.handle.net/10902/520},
abstract = {Measurements of specific heat, dc magnetic susceptibility, and Yb LII and LIII x-ray absorption near-edge
structure  XANES  and extended x-ray absorption fine structure  EXAFS  on YbAl3 milled alloys are reported.
X-ray diffraction patterns are consistent with a reduction in particle size down to 10 nm and an increase in the
lattice strain up to 0.4% for 120 h of milling time. A decrease in the mean valence from 2.86 for the unmilled
alloy to 2.70 for 120 h milled YbAl3 is obtained from the analysis of XANES spectra. From the analysis of
spectra in the EXAFS region, an increase in the mean-square disorder of neighbor distance with milling time
is detected in good agreement with the results of x-ray diffraction. Size effects strongly influence the magnetic
and thermal properties. The value for the maximum of the magnetic susceptibility decreases around 30% for
120 h milled alloy and an excess specific heat, with a peak around 40 K in the milled samples, is derived.
These changes in the physical properties along the milled YbAl3 alloys are associated with the reduction in
particle size. Such a reduction leads to the existence of a large number of Yb2+ atoms at the surface with
respect to the bulk affecting the overall electronic state.},
publisher = {American Physical Society},
publisher = {Physical Review. B, Condensed matter and materials physics, vol.78, 2008, article number 094412.},
title = {Reduction of the Yb valence in YbAl3 nanoparticles},
author = {Rojas Pupo, Daniel and Fernández Barquín, Luis and Espeso Martínez, José Ignacio and Rodríguez Fernández, Jesús and Chaboy, J.},
}