Awana, V. P. S. and Tripathi, Rahul and Balamurugan, S. and Kumar, Anuj and Dogra, Anjana and Kishan, H. (2008) Thermal hysteresis in electrical transport of charge ordered La0.5Ca0.5MnO3 manganites. Journal of Alloys and Compounds, 475 (1-2). L13-L16. ISSN 0925-8388

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Abstract

We synthesized charge ordered La0.5Ca0.5MnO3 manganites by conventional solid-state route, which crystallizes in single-phase form having orthorhombic structure with Pbnm space group. The electrical transport of the compound exhibits highly semi-conducting behaviour from 300 K down to 130 K and showed an insulator–metal transition (TMI) with a sharp peak in ρ(T). The low temperature resistance below 30 K exhibits some upturn in the ρ(T). The charge ordered state (CO) of the Mn3+/Mn4+ ions is not clearly seen as a step in ρ(T), but the same could be seen as a change in the slope of M(T) curve around charge ordered temperature(TCO). Interestingly, when the sample is cycled for the resistance (R) measurements during cooling/heating process hysteresis of 12 K is seen near TMI. The magneto-transport of the synthesized compound in 7 T field, exhibits nearly 100% magnetoresistance (MR) between TMI and TCO. The fixed temperature (400, 300, 200, 130, 100 and 5 K) MR in ±7 T field exhibited up and down cusps at all the studied temperatures. The electrical transport, large hysteresis in ρ(T) and MR results can be explained in terms of complex phase separated magnetic structure of this compound around TMI.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Elsevier B.V.
Uncontrolled Keywords:	Magnetically ordered materials; Gas–solid reactions; X-ray diffraction; Magnetic measurements
Subjects:	Chemistry Materials Science Metallurgy & Metallurgical Engineering
Divisions:	UNSPECIFIED
Depositing User:	Ms Neetu Chandra
Date Deposited:	22 Oct 2012 11:49
Last Modified:	22 Oct 2012 11:49
URI:	http://npl.csircentral.net/id/eprint/742

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