Low-Temperature Electronic Properties of the Lan+1NinO3n+1 (n = 2, 3, and ∞) System: Evidence for a Crossover from Fluctuating-Valence to Fermi-Liquid-like Behavior
✍ Scribed by K. Sreedhar; M. McElfresh; D. Perry; D. Kim; P. Metcalf; J.M. Honig
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 645 KB
- Volume
- 110
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
Measurements of the temperature dependence of the electrical resistivity (\rho(T)), magnetic susceptibility (\chi(T)), and Seebeck coefficient (S(T)) have been carried out on the (n=2,3), and (\infty) members of the homologous lanthanum nickel oxide systems (\mathrm{La}{n+1} \mathrm{Ni}{n} \mathrm{O}{3 n+1}) that were annealed in air. With increasing (n), a progressive decrease in the electrical resistivity and a gradual change from insulating to metallic behavior are observed. (\mathrm{La}{3} \mathrm{Ni}{2} \mathrm{O}{7}) is nonmetallic, showing a gradual increase in (\rho) when (T) decreases ((d \rho / d T<0) ) from 300 to (4.2 \mathrm{~K}), whereas (\mathrm{La}{4} \mathrm{Ni}{3} \mathrm{O}{10}) and (\mathrm{LaNiO}{3}) exhibit metallic resistivity ((d \rho / d T>0)). A minimum in (\rho(T)) near (140 \mathrm{~K}) is observed for (\mathrm{La}{4} \mathrm{Ni}{3} \mathrm{O}{10}), while (\mathrm{LaNiO}{3}) exhibits a (T^{2}) dependence for (\rho(T)) below (\sim 50 \mathrm{~K}). The magnetic susceptibility of (\mathrm{LaNiO}{3}) is Pauli-like, but the (\boldsymbol{X}(T)) data for (\mathrm{La}{3} \mathrm{Ni}{2} \mathrm{O}{7}) and (\mathrm{La}{4} \mathrm{Ni}{3} \mathrm{O}{10}) below (350 \mathrm{~K}) show a decrease with decreasing temperature. The Seebeck coefficient of all these compounds is negative at high temperatures; (\mathrm{La}{3} \mathrm{Ni}{2} \mathrm{O}{7}) and (\mathrm{La}{4} \mathrm{Ni}{3} \mathrm{O}_{10}) exhibit a sign change in (S) at low temperatures. These results suggest a crossover from a fluctuating-valence to a Fermi-liquid-like behavior with increasing (n). O 1994 Academic Press, Inc.