G. Grimvall et al., SPIN FLUCTUATIONS IN PARAMAGNETIC CHROMIUM DETERMINED FROM ENTROPY CONSIDERATIONS, Physical review. B, Condensed matter, 47(22), 1993, pp. 15338-15341
We have analyzed the entropy of paramagnetic bcc Cr from the Neel temp
erature T(N) = 311 K to the melting temperature T(f) =2136 K. It is sh
own that the total experimental entropy cannot be accounted for solely
by a sum of a vibrational part and a Sommerfeld-type electronic term
from a nonmagnetic electronic structure. The total entropy is obtained
through an elaborate assessment of available experimental data on var
ious thermodynamic properties. The vibrational part is based on phonon
data obtained in neutron scattering experiments by Trampenau, and acc
ounts also for anharmonic effects. The Sommerfeld-type electronic part
is obtained from electron band-structure calculations. Our analysis s
uggests a magnetic contribution that is related to spin fluctuations a
nd that increases with temperature. We compare Cr with the other group
-VI transition metals, Mo and W, using results from our previous works
. Cr, Mo, and W show striking similarities, e.g., in their anharmonic
phonon softening, when considered as a function of the reduced tempera
ture T/T(f), where T(f) is the melting temperature. Since phonons domi
nate the heat capacity, their C(p) vs. T/T(f) plots are very similar.