Effects of Ca substitution on the magnetic properties in La1-xCaxMn0.90Cu0.10O3 (x=0.05–0.30) manganites

Abstract

Systematic AC and DC magnetic measurements were carried out to investigate the magnetic properties of La1-xCaxMn 0.90Cu0.10O3 (x=0.05-0.30) system. A striking paramagnetism (PM) to ferromagnetism (FM) transition is observed at the FM ordering temperature TC. Below TC, the samples with x≤.0.20 show a visible unexpected drop in zero-field cooled (ZFC) DC magnetization curves near 100 K, which is believed to be associated with the domain wall pinning effects. As for the sample with x=0.30, there is no anomalous behavior near 100 K, while another different magnetic phase transition is shown up below 50 K in both FC and ZFC curves. Detailed experimental results show that the phenomenon is resulted from the phase competition rather than solely magnetic interactions. © 2009 IOP Publishing Ltd.