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ISRN Materials Science
Volume 2013 (2013), Article ID 490798, 8 pages
http://dx.doi.org/10.1155/2013/490798
Research Article

Magnetotransport Behaviour of Nanocrystalline ( )

1Department of Physics, National Institute of Technology, Kurukshetra 136119, India
2Department of Applied Physics, Delhi Technological University, Delhi 110042, India
3National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India
4Centre of Nanotechnology, Indian Institute of Technology, Roorkee 247667, India

Received 16 July 2013; Accepted 1 September 2013

Academic Editors: D. M. Chipara and C. Carbonaro

Copyright © 2013 Neelam Maikhuri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The nanocrystalline samples of (PSMO) ( , 0.50, 0.55, and 0.60) were synthesized by wet-chemical sol-gel route. Structural, magnetic, and magnetotransport properties have been studied systematically. It is found that samples with Sr content and 0.50 show paramagnetic to ferromagnetic (PM-FM) transition at  K with no trace of FM-AFM transition within the temperature range of 77–350 K. However, interestingly a second transition is observed at 273 and 255 K, respectively, for samples and 0.60 correspond to an A-AFM magnetic structure. This indicates that samples and 0.50 are ferromagnetic below , while other samples ( and 0.60) have a mixed phase consisting of FM and A-type AFM phases. Resistivity versus temperature (ρ-T) curve shows that the resistivity of all the samples is much larger than the single crystals of corresponding compositions due to large contribution of grain boundaries in the present nanocrystalline samples. Moreover, the decrease in metallic component at higher Sr concentration is also evidenced by the successive reduction in magnetoresistance (MR) with increasing Sr content from to 0.60.