https://doi.org/10.1140/epjb/e2010-00287-x
Thermal expansion and elasticity of PdFe3N within the quasiharmonic approximation
1
Materials Chemistry, RWTH Aachen University, 52056 Aachen, Germany
2
Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany
Corresponding author: a music@mch.rwth-aachen.de
Received:
24
June
2010
Revised:
17
August
2010
Published online:
27
September
2010
We have explored the bulk modulus and the thermal
expansion of PdFe3N (space group 
) using ab initio phonon
dynamics within the quasiharmonic approximation in the temperature range
from 50 to 1000 K. PdFe3N possesses a linear thermal expansion
coefficient common for typical ceramics. The calculated average linear
thermal expansion coefficient of 6.4 × 10-6 K-1 is
consistent with the average measured coefficient of 6.7 × 10-6 K-1. We have shown here that the thermal behavior of this compound can
be understood based on the electronic structure and the lattice dynamics
thereof. PdFe3N exhibits both metallic as well as covalent-ionic
bonding. The Fe–N covalent-ionic bonding suppresses the lattice vibrations
of the PdFe3 matrix. The bulk modulus of 188 GPa for PdFe3N
decreases by 15% in the temperature range studied, which is expected due
to presence of stiff Fe–N bonds.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010
