Anomalous thermal conductivity in Nd＿1.67Sr0.33NiO＿4

Abstract

The temperature dependence of thermal conductivity (K),resistivity (ρ) and low field ac susceptibility (χ) of perovskite nick elates Nd＿2-xSr＿xNiO＿4(x =0.33,1.35) have been measured at temperatures from 77 to 300 K. The thermal conductivity an omalies associated with charge_order (CO) and spin_order (SO) are observed simultaneously in Nd＿1.67Sr0.33NiO＿4 for the firs t time so far as we know. The thermal conductivity is enhanced belowT_CO , but is suppressed near T＿SO. There is also response to CO and S O in the χ-Τ curve. Only CO is observed in the ρ-Τ curve. In contrast, th ere are no anomalies in K-Τ, ρ-Τ andχ-Τ of Nd＿1.67Sr0.33NiO＿4. The anomalous phonon thermal conductivi ty in Nd＿1.67Sr0.33NiO＿4 indicates that there are strong charg e_phonon interaction and the spin_phonon interaction in this compound.