Electrical conduction mechanism for the investigation of charge ordering in Pr < inf > 0.5 < /inf > Ca < inf > 0.5 < /inf > MnO < inf > 3 < /inf > manganite system

Abstract

In the present work, a systematic investigation of electrical transport mechanism has been used as a tool to investigate the charge-order suppression and its crossover in Pr0.5Ca0.5MnO3 (PCMO) manganite system with varying particle size and applied magnetic field. The samples with different particle sizes were synthesized by adopting sol-gel method and sintering at different temperatures. The prepared samples were thoroughly characterized by various physicochemical techniques. The activation energy and density of states at Fermi level obtained from the temperature-dependent electrical resistivity data clearly show the charge order crossover signatures and its suppression in the samples below 70 nm particle size and applied magnetic fields above 4 T. The significant change in various electrical transport parameters with the particle size around 70 nm could be attributed to the melting of long-range charge ordering behavior due to surface spin disorder and induced lattice-strain effects in PCMO manganite system.