X-ray diffraction and resistivity measurements were carried out on La 1.85 Sr 0.15 Cu 1−x M x O y (La: 214) ceramic samples with different doping elements M and doping contents x (M = Li, Ni, Co and Mn, and x = 0.00, 0.15 and 0.30). It is found that the substitutions of the above dopants at Cu sites cause lattice deformation and lead to the largest change in the transport properties of La: 214 systems. The pure sample with x = 0.00 exhibits superconductivity at 36 K, while the samples with x = 0.15 and 0.30 show semiconductor-like behavior with decreasing temperature from 300 K down to 20 K. The magnetic doping samples show a rapid increase in the resistivity more effectively than samples with the nonmagnetic dopants. The rate of increase in the resistivity with doping follows the order Mn > Co > Ni > Li. On the other hand, the activation energy E a is calculated in the three different temperature regions characterized in the (ρ-T ) curve. A good correlation in the behavior of E a as well as resistivity with dopants is reported. Our data fit well with the Arbrikosov and Gork'ov theory, but disagree with those of Huang et al (2005 Physica C 421 56). Our comments on Huang et al's samples are reported.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.