Abstract
We report the resistivity, thermopower, and dc susceptibility of R (R=La,Pr) ceramic samples for 1.4 K≤T≤300 K. The resistivity of shows a dependence below 80 K and changes over to a dependence at higher temperature (100–300 K). The resistivity of exhibits a metal-insulator transition at =130 K with a linear temperature dependence above . The thermopower of both and is linear and negative in the metallic region. The susceptibility of is Pauli-like with a Curie-Weiss contribution at low temperature. The Pauli term is enhanced well above the free-electron value. Our samples have smaller resistivity and larger resistivity ratio than previously reported. Thermogravimetric analysis shows that there is excess oxygen (δ>0) in our samples of , which suggests that the oxygen content of is important for its physical properties.
- Received 28 December 1992
DOI:https://doi.org/10.1103/PhysRevB.48.1112
©1993 American Physical Society