Abstract
The effect of grain connectivity on the magnetoresistance (MR) was studied on porous and highly dense polycrystalline bulk samples of La 0.7Ca 0.3MnO 3 and La 0.8Li 0.2MnO 3 synthesised by conventional solid state reaction and partial melting technique. SEM and XRD investigations demonstrated that the partial-melted samples were very dense with large grain sizes whereas the porous sample contained large numbers of small sized grains. The porous La 0.7Ca 0.3MnO 3 and highly dense La 0.8Li 0.2MnO 3 samples exhibited a very wide transition width in resistance vs. temperature ( R− T) plots taken in magnetic fields of 0.3 or 1 T over a wide temperature range from 77 to 235 K. In contrast, the partially melted La 0.7Ca 0.3MnO 3 sample only showed a very sharp transition around the ferromagnetic transition at 235 K in the R− T curve. It is proposed that it is the grain connectivity and not the density of the samples that is responsible for the transition width in R− T.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
