Anomalous pressure dependence of the Kadowaki-Woods ratio and crystal-field effects in mixed-valence YbInCu4.
The mixed-valence compound was investigated by electrical resistivity and ac specific heat at low temperatures and high pressures. At atmospheric pressure, its Kadowaki-Woods (KW) ratio A/gamma2 is 16 times smaller than the universal value RKW(=1.0x10(-5) microOmega.cm.mol2.K2.mJ-2), but sharply increases to 16.5RKW at 27 kbar. The pressure-induced change in the KW ratio and deviation from RKW are analyzed in terms of the change in f-orbital degeneracy N and carrier density n. This analysis is further supported by a dramatic change in residual resistivity rho0 near 25 kbar, where rho0 jumps by a factor of 7.
Park
Tuson
T
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Sidorov
V A
VA
Sarrao
J L
JL
Thompson
J D
JD