ORBi: Bhame Shekhar - La0.7Ca0.3MnO3 / Mn3O4 composites: does an insulating secondary phase always enhance the low field magnetoresistance of manganites?

Reference : La0.7Ca0.3MnO3 / Mn3O4 composites: does an insulating secondary phase always enhance the...


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Chemistry Physical, chemical, mathematical & earth Sciences : Physics
	To cite this reference:	http://hdl.handle.net/2268/112480

Title :	La0.7Ca0.3MnO3 / Mn3O4 composites: does an insulating secondary phase always enhance the low field magnetoresistance of manganites?
Language :	English
Author, co-author :	Bhame, Shekhar [Université de Liège - ULg > Département de chimie (sciences) > Chimie inorganique structurale >]
	Fagnard, Jean-François [Université de Liège - ULg > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques >]
	Pekala, Marek [Warsaw university > > > >]
	Vanderbemden, Philippe [Université de Liège - ULg > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques >]
	Vertruyen, Bénédicte [Université de Liège - ULg > Département de chimie (sciences) > Chimie inorganique structurale >]
Publication date :	2012
Journal title :	Journal of Applied Physics
Publisher :	American Institute of Physics
Volume :	111
Pages :	063905
Peer reviewed :	Yes (verified by ORBi)
Audience :	International
ISSN :	0021-8979
City :	Melville
Country :	NY
Keywords :	[en] magnetoresistance ; manganites ; composites
Abstract :	[en] Composites of magnetoresistive La0.7Ca0.3MnO3 (LCMO) with insulating Mn3O4 are useful as a model system because no foreign cation is introduced in the LCMO phase by interdiffusion during the heat treatment. Here we report the magnetotransport properties as a function of sintering temperature Tsinter for a fixed LCMO/Mn3O4 ratio. Decreasing Tsinter from 1250°C to 800°C causes an increase in low field magnetoresistance (LFMR) that correlates with the decrease in crystallite size (CS) of the LCMO phase. When plotting LFMR at (77 K, 0.5 T) vs. 1/CS, we find that the data for the LCMO/Mn3O4 composites sintered between 800°C and 1250°C follow the same trend line as data from the literature for pure LCMO samples with crystallite size > ~25 nm. This differs from the LFMR enhancement observed by many authors in the "usual" manganite composites, i.e., composites where the insulating phase contains cations other than La, Ca or Mn. This difference suggests that diffusion of foreign cations into the grain boundary region is a necessary ingredient for the enhanced LFMR.
Funders :	Université de Liège ; Wallonie-Bruxelles-International ; Polish Ministry of Science
Name of the research project :	D09/09
Target :	Researchers ; Professionals
Permalink :	http://hdl.handle.net/2268/112480
Mentions required by the publisher for OA :	Copyright (2021) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 111, 063905 (2012) and may be found at http://jap.aip.org/resource/1/japiau/v111/i6/p063905_s1.

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